Some fertility drugs substantially increase the probability of multiple births.
[ACOG Technical Bulletin 120. Medical Induction of Ovulation. September
1988.] In vitro fertilization techniques can also result in multiple gestations if
more than one embryo is introduced, with a rate of twins of 15% to 18% and
of triplets of 1% to 2% with four preembryos. [ACOG Technical Bulletin 140.
New Reproductive Technologies. March 1990. [ACOG Technical Bulletin 140.
New Reproductive Technologies. March 1990.] Multiple gestation poses grave
risks to both the fetuses and the mother. [ACOG Technical Bulletin 120.
Medical Induction of Ovulation. September 1988.] These risks should be
explained in detail. The woman must understand that the risk is not that she
will have twins or triplets (or more) but that one or more of the babies may be
severely disabled and that she may suffer medical complications. The physician
should also discuss the possibility of pregnancy reduction and selective fetal
termination. A woman with multiple gestation must be informed of her options:
1. Abort all fetuses
2. Attempt to carry all fetuses to term
3. Terminate some of the fetuses [ACOG Committee on Ethics, Committee
Opinion 94. Multifetal Pregnancy Reduction and Selective Fetal Termination.
The introduction of multiple preembryos is intended to increase the success
rate of in vitro fertilization. This benefits the patients by reducing the cost and
medical risks of multiple procedures, but it is also critical to the success of the
fertility center’s marketing. Few persons would be willing to undergo the risk
and expense of in vitro fertilization if the success rate were only 3% to 4%.
Physicians have a duty to ensure that patients understand this trade-off
between success and the attendant risk of multiple births.
The physician should also discuss the possibility of amniocentesis on the
individual fetuses and the termination of those with genetic diseases. This is a
dangerous process, however, because it is usually done later in the term, and
retained fetal tissue can cause disseminated intravascular coagulation, with
fatal consequences for the mother. [Novick LF, et al. New York State HIV
Seroprevalence Project, Chapter II Newborn Seroprevalence study: methods
and results. Am J Pub Health Supp. 1991;81:15–21.]