Prenatal Genetic Screening – So many choices

Medicine is always changes, and its hard to keep up with the changes.  One good example is prenatal genetic screening.  It originally started as a screening test for anencephaly and spina bifida, and has now progressed to a wide variety of tests (all with their own acronyms of course):

NT – Nuchal translucency, a first trimester ultrasound.  Assigns a risk for Downs Syndrome, may identify a risk for congenital heart disease.

FTS – First trimester screen (labs and NT scan).  Better prediction that NT alone, fewer positive tests in women with normal fetuses.

IPS – Integrated prenatal screen (labs in the first trimester and second trimester and NT scan).  Even better test, but the results are delayed until the second trimester.  May identify placental dysfunction concerns.

SIPS – Serum integrated prenatal screen (labs only, no ultrasound).  In women under 35 the detection rate is similar to the detect rate for IPS in women over the age of 35.

Quad Screen – second trimester labs only.  Not the preferred screening test, as it has a high false positive rate.  More women will be labelled at risk, but have a normal fetus.

NIPT – Non invasive prenatal test (maternal sample any time after 10 weeks, screen for fetal DNA fragments).  Only test that is looking at DNA, not hormones released by the placenta.  Very low false positive rate, but often cost money out of pocket as it is not yet covered by many plans.

Details on each test can be seen here.

What do these tests have in common?  The lab parts actually don’t test the baby, they test the placenta.  Ultrasound is the only test that is actually looking at the baby.  Excluding NIPT, the other tests look a variety of hormones that are produced by the placenta.  The concentration of these hormones varies with gestational age, and by the number of fetuses.  It is important to understand that these are screening tests, they don’t give you a diagnosis, but a risk of there being a problem.  This can lead to anxiety and more testing (ultrasound and possibly amniocentesis).  However, the benefit of these tests is on a population basis, as most women will test negative.  That means they are at low risk for the problem, and can be reassured.

These tests are fairly limited in what they look for.  Humans have 23 pairs of chromosomes, one inherited from each parent.  Downs syndrome mean the fetus has trisomy 21 (an extra chromosome 21).  The other two common syndromes we screen for are trisomy 18 and 13.  Spina bifida and anencaphaly are defects of the neural tube, leaving openings at the top of the fetal skull or in the spine.  That is all these tests look for.  Some times the placenta will be identified to have a pattern of hormones that is associated with an increased risk of complications later in pregnancy, but these tests don’t identify all or even a significant number of these placentas.  These tests don’t identify genetic problems inherited from parents.  They don’t predicted developmental problems.  They won’t identify pregnancies at risk for autism.

For the individual women with positive tests, it can be scary.  However, it is important to remember that a screen positive does not mean that there is anything wrong with your baby.  Rather is highlights an increased risk, but in most cases things will still be fine.  For example, the test is considered positive at about a risk of 1 in 200 that the baby will have a common chromosome problem.  That means 199 babies with the same results will be normal, only one will be affected.  Even a result of 1 in 2 risk is not a diagnosis.  Have the the amniocentesis will reveal a normal fetus.

The hard part is to determine how mush risk you are comfortable with, and how badly you want to know the diagnosis.  If you are unwilling to continue a pregnancy with a baby with Down’s syndrome, your threshold to do an amniocentesis may be different than for a couple who would continue the pregnancy.  That is because there is a risk to the procedure – a 1 in 200 risk of complications.  This includes infection, rupture of membranes and loss of the the pregnancy all together.  The role for NIPT comes in here, it is a great screening test, and is nearly as good as a diagnostic test.  Again it is most useful for its negative results.  If a women has a different screening test that is positive for Downs syndrome, she can choose NIPT before an amniocentesis, because a negative NIPT is very reassuring.  If the test comes back positive, we still recommend an amniocentesis to confirm the diagnosis prior to making any decisions about terminating a pregnancy.

The reason to choose genetic screening is personal.  Some women choose the test for the reassurance it offers.  Some choose the test because they know they would terminate a fetus affected with Downs syndrome.  Some choose the test because they don’t want to be surprised by a life altering diagnosis at the birth of their child.  As a physician, the test help me evaluate the pregnancy.  If there are markers of Downs syndrome on ultrasound, it is nice to compare to the screening results because it affects the risks we estimate.  If we identify a baby with Downs syndrome, we monitor the pregnancy differently because they are at increased risk for structural problems, and an increased risk of stillbirth.  We make sure there is a pediatrician at the birth to help the infant if there are any problems.  The test is not a seek and destroy mission, but rather a chance to provide couple more information and choices as they become parents.

Advertisements

10 Minutes is not enough time.

Have you ever tried to hold your breath for ten minutes? Its not actually that easy to do. When I was competitive in synchronized swimming, I was able to get to able up to two minutes. Not spectacular, but not bad (I was eleven at the time). I still swim laps on a single breath because it was the way I tried.

However, how can I ask a baby, without any training whatsoever to hold their breath for ten minutes? I am often surprised that women think that home birth is as safe as hospital birth, and then in the same breath say that the hospital is only ten minutes away. I learned very early in training that ten minutes can be a very long time, and most babies don’t have intact brains after that time.

Compare the following two stories – both true, but long enough ago and identifiers removed.

Case 1:
Mom really wanted a VBAC. She had a vaginal delivery for her first, but that was a small infant born four weeks early, something around 5 1/2 lbs. Next baby held on to 41 weeks and weighed over 8 lbs. labour stalled at 8 cm for several hours before she consented to a c-section. For her next pregnancy, she decided to have a home birth, but again went to 41 weeks. Her midwife encouraged her to deliver in hospital, especially because this baby was palpating large. She refused. She found support to have people with her to deliver at home. They became concerned when she had been labouring for 12 hours without progressing to transition. They broke down and called the midwife, who came to her house to again encourage her to transfer to the hospital. She refused, and legally the midwife had to stay. The midwife called the hospital to left them know of an attempted HBAC and that she was encouraging them to come in. The hospital already had a copy of her records. Of the next two hours, there was no progress, and the midwife call a more senior midwife to see if they could convince the mother to transfer. The midwife had already gotten an IV started, and continue to discuss with her client and family that this was not looking promising. Shortly after the arrival of the second midwife the patient complained of increasing pain. On examination, there was increasing bleeding and the baby was no longer palpable in the pelvis. The midwife correctly identified a rupture and called 911. A second IV line was started and on route to the hospital, her blood was taken to be dropped of in the lab for emergent results upon arrive to hospital. The midwife called the OB on call (in house with anesthesia) to update them on the clinical scenario. Upon arrive, the patient were brought directly to the operating room for assessment. She was unstable and fetal heart rates were undetectable. An emergency c-section was performed to deliver a stillborn infant. Mom had a hysterectomy, but actually did ok. Time from rupture to delivery was only 30 minutes. I am not sure how things could have possibly gone more smoothly or faster for a homebirth transfer. I was impressed with the midwives and hospital team. They saved this woman’s life, but it was unfortunately too must time to save the baby.

Case 2:
A mom tried to have a homebirth for her first, but ended up transferring in and having a c-section. She was determined to do it “right” the next time, but decided to try in hospital after discussing options with her midwife. She needed an induction at 41+3 days. We used a cervical catheter, AROM and eventually oxytocin. She had continuous electronic fetal monitoring. Eventually she asked for an epidural. She too suddenly had increased pain. The oxytocin was stopped and mom was examined. No presenting fetal part and heavy vaginal bleeding. A second IV was started as she was transferred to the OR. She had already had a sample sent to the lab and blood was requested. An emergency c-section was performed, and the baby was in the abdominal cavity. Baby needed resuscitation, but eventually did fine without any long term consequences. Mom saved her uterus and has had a third baby by elective c-section. Time from rupture to delivery was 7 minutes. Still a long time to hold you breath, but at least the baby has a chance.

Yes, uncomplicated deliveries are exactly that – uncomplicated. But there are known complications that occur at predictable intervals. If there is a 0.5% chance of uterine rupture, most women will concern it low risk. Consider the obstetrician who works in a center with 4000 deliveries a year. If only ten percent of those are VBACs, they will likely see at least 2 ruptures a year. That is scary enough. A patient with a rupture at home is more scary. I might be able to save the mom, but by the time they identify the problem, arrange transportation and contact me, I likely won’t be able to save the baby.

Help is no just “10 minutes away”. Not if you are at home.

TTTS – What is that??

Obstetrics is full of acronyms.  One of those that can inspire fear and fascination even in a perinatologist is TTTS (Twin-twin transfusion syndrome).  Such a simple name, such a complicated disease.

Twins come in many different varieties.  It is those that share a placenta that have the potential for this unique complication.  Because the placenta is shared, their blood volume is shared.  As we know, sharing is not always equal.  This is not a disease that a mother can cause or prevent, it is a known complication of a shared placenta.  We know is can be mild or severe, it can progress slowly or quickly, and some times is can even correct it self.  There are some treatment options, but there are risks to each of the choices.

The twin that is giving blood is call the donor.  It is frequently smaller, but not always.  In mild disease, it will develop low fluid.  Next is lower blood pressure leading to decreased blood supply to the kidneys, so less urine production, in more severe cases this baby will have an empty bladder.  More severe disease will be associated with blood flow alterations in the baby, possibly leading toe heart failure (hydrops) and death.  The twin receiving blood is the recipient.  Again, although this twin tends to be the larger twin, this is not always the case.  This baby will receive extra blood and therefore extra fluid.  They have more fluid, so they pee more and may develop excessive fluid.  This baby is also at risk for alterations is blood flow, heart failure and death.

A placenta is made of a multiple functional units called cotyledons.  Each unit has an arterial supply from the umbilical cord and a vein that brings the oxygenated blood back to the baby.  You can image the placenta represented by a complex of small circles. (ttts1)

Each baby develops its umbilical cord independently.  Each functional unit is attached to an umbilical cord.  There may not be an equal distribution of cotelydons, one baby may start off with a greater share of the placenta from the beginning, and this may contribute to difference sizes in the twins.  Dark red on the left is twin A, light pink on the right is twin B. (ttts2)

Each functional unit also has a vein returning to the umbilical cord.  For the most part, the veins and arteries are paired.  Veins for A are dark blue and for B they are light blue. (ttts3)

So far, we have only examined the part of the placenta that is unique to each baby.  Because the babies share a placenta, there must be connections in the blood vessels.  There are three types of connections: arterial-arterial, vein-vein and arterial-vein.  Each has a different impact on the outcome of the pregnancy.

A-A connections.  These are actually the least common in healthy mono/di twins.  There are often implicated in more serious twin conditions (like TRAP sequence).  Because they are both high pressure vessels, there is not a lot of flow between the babies.  See the connection highlighted with the yellow ring. (ttts4)

V-V connections.  These are the good connections.  The more V-V connections, the less risk there is for TTTS.  These are both low pressure vessels.  Blood will flow in the direction of least resistance (or from higher to lower pressure).  If the babies are sharing blood unequally, these are the “escape valve” that allow the blood to travel back to the donor baby.  Unfortunately, as the disease progresses, the pressure from the excessive amniotic fluid in the recipient twin can actually compress these vessels.  When the escape valve is closed, the disease can suddenly progress quickly. (ttts5)

A-V connections.  These are the ones that cause problems.  They are not direct vascular connections.  Rather one baby supplies and artery to a cotyledon and the other baby supplies the vein.  Yellow circles show cotyledons supplied by baby A, orange from baby B.  (ttts6)

Because the functional units are made up of microscopic blood vessels that allows the transfer of nutrients and oxygen, these connections are essentially one way.  The blood goes from one baby via the artery to the other baby via the vein.  Plus the receiving baby receives the nutritional benefit, while the other baby does the work to supply the blood. (ttts7)

TTTS occurs when there is a net transfusion in a single direction.  If there are only two A-V connections and one goes each direction, this is likely to be well tolerated.  It is when there is a disproportional flow in one direction, particularly with fewer V-V connections to allow the blood to equalized, there is a risk for TTTS.  This occurs in about 15% of mono/di twins.  Not surprisingly, the most effective treatment we have is to disconnect the A-V connections and stop the one way flow.

Unfortunately, it is difficult to assess the placental blood vessels in pregnancy.  When surgery is performed to treat TTTS, the surface vessels are mapped.  It has been attempted to do this with ultrasound, but is it not a reliable why to screen for TTTS.  The best we can do it assess these babies every two weeks to assess the fluid in each sac.  If you are pregnancy with twins who share a placenta, please ask for you ultrasounds at a minimum of every two weeks from 16 weeks onward.  If there is a difference, the patient needs to be referred to perinatology.  If TTTS is diagnosed, they will then need to be referred to a treatment centre, as the surgery for this disease is highly specialized and concentrated into a few centres.

**This is my first attempt to draw my own picture for the blog.  The diagrams are based on the ones I draw for my patients when explaining the risks associated with mono/di twin.  They are all PDF attachments**

All Twins are Not Equal

Twins are a serious concern.  There is a general lack of information and knowledge about them.  They are not good or exciting.  The only twins that I imagine to be good are those that are at least five years old, healthy and attending school.  Finally a break for the parents.  Twins are a lot of work.  Unfortunately, it has become more frequent to see twins, and there are being posted all over the internet.  It is concerning about the lack of understanding about the serious and life threatening risks that twins face.  They are lucky (in some cases) just to make it through pregnancy and survive.

Take for example a recent picture posted on Facebook.  I won’t show it here, but this is a link to it (I hate to admit that I visited this page, but it is a good place for a laugh or just to let of steam yelling at the screen).  The argument is this:  twin A is pale because of early cord clamping and twin B is darker because of delayed cord clamping.  I call it a bunch of people talking about something about which they have very little knowledge or information.  In the discussion, they clearly mention that this was a “mono” pregnancy, but then seem confused what this means.  If you don’t know the different types of twins, for bloody sakes, DON’T GIVE OUT MEDICAL INFORMATION about TWINS!!

Here is my twin primer.

Zygosity – refers to the number of eggs involved in the conception

Monozygotic – one egg fertilized, and then split into twins.  These are “identical twins“.  They are the same sex.

Dizygotic – two egg fertilized, two fetuses develop.  These are “fraternal twins“.  They can be the same or different sexes.

Simple so far?  Most twins are dizygotic, and this is especially so if the pregnancy results from infertility drugs.  In Canada, about 2/3 of twins are dizygotic.

Chorionicity – refers to the number of chorion (for easy remembering, this is the outer sac and placenta).

Dichorionic – Two chorions.  All dizygotic pregnancies (two fertilized eggs) results in dichorionic pregnancies.  Because there are two placentas and two outer sacs, there must also be two inner sacs (amniotic sac) so these pregnancies are also diamniotic.  Now where this starts to get complicated is sometimes the two embryos implant very close to each other.  Their placentas may touch or even be called fused.  This just refers to what can be seen on ultrasound; the placentas are not actually fused, there is no shared placenta or blood volume, and when delivered, it is not difficult to separate the two placentas.  Identical twins, if the sepearation of the one egg occurs before three days, two distinct embryos will develop, each with their own placenta.  Although they are identical, they do not share a placenta or blood.

File:Placentation.svg

Monochorionic – These MUST be identical twins, but not all identical twins are monochorionic.  These are twins that separated from a single egg between days 3-8 after conception.  They represent 2/3 of identical twins.  The separation occurs after the cells that are destined to be the placenta have developed separately from the embyro(s).  This means they share a placenta.  If they share a placenta, they share the blood vessels associated with the placenta, and therefore are likely to share their blood volumes.  These are more complicated twins and anyone who says otherwise has absolutely no clue what they are talking about.  Think about this way, these twins are conjoined at the placenta!!  These twins have only one external sac, and are further classified as to the number of internal sacs (amnions).

Monochorionic-Diamniotic – These twins share a placenta, but each have their own internal sac.  There are essential only two thin membranes between the twins (the amnion for each twin).  They are joined at the placenta, and almost universally share their blood volumes.  However, babies are not known for their sharing skills!  Due to the organization of blood vessels in the shared placenta, it is possible to have an unequal distribution of fluid (blood) and/or nutrients.  Twin-Twin transfusion syndrome (TTTS) is a condition whereby one twin (the donor) is slowly and consistently given its blood volume to the other twin (the recipient).  This occurs in 15% of mono-di twins.  If they don’t share equal portions of the placenta, they will not receive equal nutrition from the mother.  This can lead to one of the babies becoming severely growth restricted.  This also occurs in 15% of mono-di pregnancies.  Even more complicated is when both situations occur at the same time, generally not a good outcome for one or both twins.  These conditions can only be reliably identified with ultrasound and routine screening for these pregnancies will improve outcomes (there are some treatment options).  I promise a future post just about TTTS, I owe it to a friend who lost a baby to this condition.

Monochorionic-monoamniotic – These twins not only share a placenta but share a sac.  These twins separate later, but days 8-12.  These are much more rare, accounting for 1% of monozygotic twins.  This is a very dangerous situation, because they are at risk for all of the other complications with a shared placenta, plus they can tangle their cords and make knots.  This is risky because it can cause one or both twins to die.  The most risky time for these twins is labour.  They are all delivered by elective c-section at 32-34 weeks.

There are other more rare conditions, which as a perinatologist, find very interesting.  However, I would be happy if health care providers and the so-call child birth educators could just get these basics right.  Twins aren’t good, shared placentas are worse.

Back to the picture in discussion.  Do I really think this difference is cause by delayed cord clamping of only one baby??  Absolutely not.  This is a pathological image where one baby is clearly anemic (low red blood cells) and the other is polycythemic (too many red blood cells).  This did not happen at delivery, these babies would have looked exactly the same if delivered by c-section and both cords clamped at the same time.  Reading the site where the picture was posted, they even comment on the fact that the darker twin needed more help.  This isn’t surprising to someone who routinely cares for complicated twins.  Generally, the smaller anemic twin is more fiesty than the bigger polycythemic twin.  The little twin has been fighting to get its fair share, perhaps a little stressed and ready to get out of there.  The bigger twin just got everything given to it, had a cushy environment and is generally not ready to be delivered.  Sudden it has to work to survive – this is why they often need help.  Plus they have extra red blood cells to break down, so they are also at risk for jaundice.

If only twin B had delivered first and had early cord clamping and then twin A second with delayed clamping.  That would have fixed everything, right??  If we are suppose to trust birth, why didn’t these babies just come out in the right order?

Time to get back to work

When I first started this blog, I really didn’t know what to expect.  I have been off work for a few months for medical reasons, and I realized during that time that I actually missed writing.  Also, being a patient again reminded me how much goes on in medical care that the average patient may not realize.  Although the Canadian system is not perfect, it does allow for timely access when needed.  We just need to know who to ask for help.

A good example of this is access to MRI.

I hurt myself, and one of the ways to investigate it is an MRI.  First I had to see my GP, who than referred me to a specialist.  The specialist agreed with my GP and order the MRI.  The request was sent in, and I received a letter from the hospital, with a date for my MRI six months later.  I was reminded to keep my appointment, because of long waiting lists, if I no longer needed this test by the time it came around, I should phone an cancel so that someone else could use that appointment time.  This seemed like a long wait, particularly because it was part of the problem that was keeping from work.  I called the department, and asked if there was anyway to get an earlier appointment.  I was placed on a cancellation list.  I was a little unusual, in that I could be available in less than 30 minutes for the MRI because I worked in the hospital.  Lucky for me, within two weeks of returning to work, I was given an earlier time and had my pictures taken.  Unfortunately, there is a delay in reading the MRI because it is a specialized joint that needs to be looked out.  The radiologist with the most experience was gone and wouldn’t be back for a week.  Doesn’t matter, I will still able to get my answers quickly.  I will admit to letting the booking clerk know that I was a physician at the hospital, but I like to think that this cancellation list is available to all patients.  Overall, it took 12 weeks to figure out what was wrong and get me totally back to work.

However, when needed, MRI’s can be accessed more quickly.  I have had several patients in the last year who had complicated pregnancies – either concerns about invasive placentas, unusual locations of placenta or fetal brain anomalies.  In all of these cases, I was able to advocate for my patients and arrange the MRI’s quickly.  This is because it clinically made a difference to know immediately what the concern was, as opposed to my joint pain, which really could wait.  Although we live in a society of instantaneous gratification, it is hard to remember that there are many patients in the system who are sicker and have more urgent needs than you.  Those who have urgent need are treated urgently.  And there was no additional cost to these families to have the testing done rapidly.  We were able to save one baby, unfortunately confirm that one was beyond our ability to help and to give the final family a clearer picture of the diagnosis their baby faced so they could determine the best course of action for themselves.

Would I have preferred to get my MRI sooner?  Absolutely!!

Would I have wanted my MRI to be done at the expense of someone else with a more urgent need?  Absolutely not!!

The Canadian system is far from perfect, but it treats people according to the severity and acuity of their condition.  Unless we are willing to pay more to have greater access for less urgent conditions, we should be happy with the care we get.  I am thankful that my MRI was covered, but I am more thankful that my patient’s MRI’s were also covered and that our system allowed for me to arrange them in the appropriate time frame.

We Can’t Save Them All . . .

I am upset when I read that “babies die in hospital too”.  Why, because we grieve each and everyone of these loses. We investigate the causes, make changes to the system and highlight concern to providers if indicated.  We meet with families, multiple time, to review all of this information.  We meet to make plans for future pregnancies, not only to provide mom a good outcome next time, because it is not always possible, but to help them feel safe and empowered to try again when they are ready.

This always seems in direct contrast to what I see on the internet.  There are unfortunately many examples of fetal and neonatal deaths at the hands of untrained and under-trained care providers.  Moms are told:

“This would have happened in the hospital”

“At least you avoided interventions”

“Trust birth, it will be better next time”

And so forth.  None of this is helpful.  Moms and families deserve to know, if possible, why they lost a child.  Often times we can find a reason, but we can exclude many causes.  Furthermore, this never addresses the rarity of an intrapartum death.  Babies don’t just die in hospital while there mothers are in labour, not unless something has really gone wrong.  This would lead to a inquest of sorts to help improve the system.  But outside the hospital, it is more of a too bad, better luck next time. 

I became a high risk obstetrician, in part because I like to help people.  A friend from high school said it best.  They wanted to be a funeral home director, not because he liked death, but rather he liked to help people through a difficult process.  That is what I do, what other well trained providers do, when there is a death.  We help the family through the process, with an entire team dedicated to helping these families.  What happens when a baby dies under the care of a CPM?  Where is the support for these women?

It is true, babies do die in hospital  We had save all babies.  However, we can help moms, and that is important too.

Safety of Homebirth

This is not meant to be a debate about home birth safety.  I just want to consider things from a slightly different point of view.  Perhaps it is not the fact that you are birthing at home that is inherently safe, but rather the fact that you are low risk enough to qualify for home birth that makes it safer.

Consider, home birth advocate are eager to  point out that they have a low rate of interventions, particularly oxytocin, epidurals and c-sections.  However, they have never had an appropriate study to rule out confounders.  In my center, if you are a healthy multiparous lady and you present in active labour, you will have less than a 5% chance of ending up with a c-section.  For first time moms meeting the same conditions, only about 10% will delivery via c-section.  This of course is not what home birth advocates are portraying.  They suggest that 1 in 3 women will delivery by c-section, suggesting that just walking into a hospital will increase your risk.  They fail to consider the multitude of other reasons why women have c-sections – breech, elective repeat, placenta complications, etc.  They also fail to consider that when we induce primips, we accept an increase risk for intervention because we have concern that leaving the pregnancy could also be associated with increased risks, and therefore acknowledge a trade off.  In my region, going post-dates with disqualify you for a home birth.  Funny thing is, going post-date will also increase the rate of c-section, whether or not you undergo an induction of labour.  Therefore it is the pregnancy complication that is increasing the risk for intervention, not the location of birth, because these women no longer qualify for home birth in the strictest sense. 

Home birth advocates also are proud to report low rates of epidurals.  This is a bit of a dumb thing to be proud of.  Who cares what an individual women wants.  Some women may feel a sense of power and control by labouring without medications, other women will feel the exactly the same by getting pain relief.  There is no inherent benefit of avoiding pain relief in pregnancy.  However, home birth advocates also fail to consider that obstructive labour can some time be improved by giving an epidural.  If mom is exhausted, in pain with all the associated catecholines, this can actually impair labour.  When you are in pain, you may naturally tighten your pelvic floor muscles as a response, therefore making labour have to work even harder to descend the fetal head.  I my experience, truly obstructive labour patterns, without cervical dilation or fetal descend may in fact be more painful.  Perhaps the women lucky enough to deliver naturally have highly progressive quick labours – they don’t have to deal with malpresentation, maternal exhaustion and frustruation.  The epidural is viewed as a negative, but for many women it is the exact opposite.  However, it must be portrayed in a negative like by home birth advocates because it is not available at home.

Finally, they promote the low use of oxytocin.  However, they fail to emphasis that women delivering at home are only women who have gone into labour spontaneously (hopefully . . . in this region they are).  That already represents a subset of all pregnant women, because it excludes comparison to any woman who has a medical or social indication for an induction of labour.

Its easier to claim they have fewer interventions and promote that it is the home birth setting and care provider that makes these differences.  However, I would argue that it is being low enough risk for a home birth that leads to the reduces need for intervention.  Home birth can be safe, but it is not the same as a hospital birth.  If you take the truly lowest risk women, the rate of severe complications with be low and may appear acceptable.  However, the rare complications occur at rates of 1 in 1000 – 1 in 10,000.  If you are unlucky enough to be one of those women, home birth won’t be safe for you or your baby.  Too bad we don’t have a crystal ball to predict who will remain low risk though delivery into the neonatal and postpartum periods.  Until, I like to have a good back up plan, and that can be done better at the hospital.  Beside, the hospital is the back up plan for home birth complications.