Higher-order multiples
Perinatal and maternal risk increases exponentially with increasing fetal number. Every woman/couple with a higher-order multiple pregnancy should have a discussion with a senior obstetrician relating to increased maternal and perinatal risks.
This should involve the tactful and sensitive discussion of the option of multiple fetal pregnancy reduction (MFPR). In addition to perinatal mortality rates, parents should be counselled as to the mean gestational age at delivery (33 weeks for triplets, 31 weeks for quadruplets). In addition, 10% of triplets and 25% of quadruplets deliver before 28 weeks' gestation, with severe neurological sequelae rates of 12% and 25% (respectively) in survivors. Higher-order multiple pregnancies should be managed in tertiary perinatal centres with a fetal medicine service (3, 11).Multifetal pregnancy reduction
To optimize maternal and fetal outcome, MFPR in the first trimester has been recommended. With MFPR, not only are there ethical considerations, but also a significant psychological impact on the parents, including emotional distress, fear, feelings of regret, and guilt. This is often compounded by the fact that the pregnancy is the result of assisted conception and the pregnancy long awaited and much wanted. The consensus views from the RCOG 50th Study Group on multiple pregnancy stated that ‘parents of high order multiple pregnancies (≥3) should be counselled and offered MFPR to twins in specialist centres' (3). The procedure is performed between 11 and 14 weeks' gestation as spontaneous reduction may occur before this (‘vanishing' fetus) and a detailed scan, including NT measurement to exclude anomalies or features of aneuploidy, may guide selection of fetuses for reduction, aiming to keep the healthiest fetuses.
Recent studies have shown that in dichorionic triamniotic (DCT) and trichorionic triamniotic triplet pregnancies, embryo reduction in the first trimester reduces the risk of preterm birth but increases the risk of miscarriage (100). In the management of dichorionic triamniotic pregnancies, MFPR to dichorionic twins by intrafetal laser is an additional option to the traditional ones of expectant management, embryo reduction by intrafetal injection of potassium chloride to monochorionic twins or embryo reduction by potassium chloride to a singleton (101).
In a recent meta-analysis of five studies, including 331 dichorionic triamniotic triplets, the miscarriage rate was shown to be 8.9% and the severe preterm delivery rate was 33.3% with expectant management; the miscarriage rate was 14.5% with a reduction of the monochorionic pair, 8.8% with a reduction of one fetus of the monochorionic pair, and 23.5% with a reduction of the fetus with a separate placenta. Severe preterm delivery rates were 5.5%, 11.8%, and 17.6%, respectively (102).
More on the topic Higher-order multiples:
- Multiple Pregnancy Resources for Professionals and the Public
- Planning timing and method of birth
- Risk Assessment and Screening for Preterm Birth in Multiple Pregnancy
- Invasive Prenatal Diagnosis in Multiple Pregnancy
- ENGAGING THE OTHER SIDE
- Assisted Conception and Multiple Pregnancy
- Management of Discordant Fetal Anomaly
- Practical Management of Vaginal Delivery in Multiple Pregnancy
- Screening for Fetal Abnormality in Multiple Pregnancy
- Induction in special situations