Karen Kerkhoff Gromada is the author of "Mothering Multiples", and other books. She is a lactation consultant and La Leche League Leader, and had a planned homebirth for a singleton baby. This post about twin birth is reproduced with her kind permission. Karen lives in the USA, so some of her comments may not apply to readers in the Britain.
I'm in favor of homebirth for uncomplicated, full-term singleton pregnancies -- I've had such a homebirth myself. Research demonstrates that such births are as safe or safer than similar births in hospitals. However, I believe twin- and other multiple births belong in the hospital because the odds are not comparable for even full-term, apparently uncomplicated vertex/vertex twins. With twins the odds start going down. And I write this as someone whose 40 5/7 week term twin pregnancy/birth, especially twin B, was the easiest of my 5 deliveries. But that's just anecdotal; as the leader of a La Leche League multiples group for more than 25 years, I've seen the odds play out in varying ways for hundreds of expectant MOT (mothers of twins). Previous pregnancy history cannot be depended upon when it comes to a twin/multiple pregnancy.
The reason being that the uncomplicated, full-term singleton (and the first of full-term, uncomplicated, vertex twins) is engaged in the pelvis, so malpresentation, cord prolapse, etc. is astronomically unlikely. The same can NEVER be said for the second (and subsequent) of multiples; that baby canNOT engage in the pelvis until the birth of the one before. This is the reason that most midwives (and their professional associations) -- including those in countries where homebirth is common -- do not recommend and will not "preside" at births at home for twins or more.
Malpresentations occur fairly often for second/subsequent multiples; cord prolapse is usually the biggest concern -- and it doesn't have to be complete to cut off a baby's oxygen, immediately placing her/him in severe distress. Placental issues, e.g. partial abruption are also acute emergencies that profoundly affects both infant(s) and mother, and these are more common during multiple births. Placenta flow issues are more of a concern with monozygotic (MZ) twins, but they may also affect dizygotic (DZ) sets in which one placenta implanted in a less favorable spot or developed in a less favorable way. Postpartum hemorrhage (with mother-related consequences) is significantly more common with twin and higher multiple births.
The issues that may result in transfer during a singleton homebirth tend to be less acute than those that occur during the birth of twins. Problems arising during a twin birth, especially for the second twin, are more likely to be true emergencies with a 5-10 minute window of time for resolution to brain injury to death.
Certainly, the odds may still be in your favor, and I respect that only you (and babies' other parent) can decide how low you are willing to go. However, you really need to investigate those odds in order to make an informed choice about birth site because this is not only about you and what you'd like; you are making decisions (that can have lifelong impact) for two (or more) other persons.
If you choose a homebirth, I hope you have made certain that your midwife has delivered a number of twins in which things that went wrong as well as twin births where all went right. Be certain she has ACLS(NN) -- Advanced Certification in Life Support (Neonatal) -- and carries related equipment. Can she and does she have appropriate IV equipment and medications if you hemorrhage?
[Note from Angela: In the UK, homebirth midwives will normally have taken the ALSO course - Advanced Life Support in Obstetrics. It is usual for midwives in the UK to carry IV equipment and they all carry medication to treat postpartum haemorrhage. In the US the situation is different and in many states midwives cannot carry these drugs.]
And be absolutely certain that she is comfortable with transfer. I've heard homebirth stories in which a mother of twins (MOT) was either not transferred when she should have been (apparently related to midwife fear of legal liability or retribution) and others in which the laboring MOT was essentially abandoned by her midwives at the hospital doorstep -- probably related to legal concerns. Since the odds of transfer are higher and the related issues more likely to be emergencies, consider distance to the hospital, consider comfort -- and consider having optional plans in place that require an obstetrician's (OB's) care prenatally so you and the OB can come to mutual agreements regarding birth if hospitaliation is necessary, allowing you to maintain some control of the situation. If you are transferred without preplanning, you will probably lose more control of the overall situation.
One thing I do want to be clear about, though, is that although I am in favor of hospital births for twins or more, I am dead set against the "one size fits all" thinking that many OB care providers have for twin/multiple births. Unmedicated birth, maternal positioning and other parental preferences, etc. are very possible for otherwise uncomplicated term or near-term twin/multiple births. The research literature supports vaginal delivery of a seconnd twin in breech or other presentation. It may take "doctor shopping" -- and I'd start by asking midwives, LLL leaders, etc. -- to find an OB who understands that she/he is your partner in birth, understands you have a right to your preferences (all things being safe at the time) and is comfortable dealing with the variations that can present, but it is a shopping expedition worth investing in. And once you find that OB provider who respects you/your choices, you will probably feel more confident in his/her judgement if any complication should arise.
Karen Kerkhoff Gromada
Karen Kerkhoff Gromada's website includes a twin/multiple birthplan which can be adapted for your own use, and articles on parenting and breastfeeding multiples (www.karengromada.com).
Twin homebirth - discussion of issues and views from mothers and midwives.
Home Birth Reference Page