CASES OF THE WEEK – “High Risk Triplet Pregnancy” by Dr Rizmee Shireen, Consultant Obstetrics & Gynaecology and Dr Hermann Ulrich Honemeyer, Consultant Obstetrics & Gynaecology

A triplet pregnancy is rather a rare event: triplet and higher order multiple births accounted for only 32.3 per 100,000 births in 1977 (before IVF) but increased to 93.0 per 100,000 births in the United States in 2018. Triplets and other higher order multiple gestations are associated with significantly increased risks of maternal and neonatal morbidity compared with twin and singleton gestations.

Prematurity at birth

The mean gestational age of delivery for triplets is approximately 32 weeks, while for twins 35, and for singletons 39 weeks. Hence, complications associated with triplet pregnancy include increased risk of prematurity, but also abnormal fetal growth including discordant growth, and an increased risk of congenital anomalies.

Fetal complications

Determination of chorionicity and amnionicity, which is ideally performed between 8 and 13 weeks of gestation, is critical for risk assessment, counseling, and pregnancy management in a triplet pregnancy. The presented case was a dichorionic triamniotic triplet pregnancy at risk for twin-twin transfusion syndrome (TTTS, also called feto-feto transfusion syndrome) and twin-anemia polycythemia sequence (TAPS), which both worsen the perinatal prognosis. Also structural abnormalities, particularly cardiac abnormalities, are more common in triplet pregnancies than in twin- and singleton pregnancies. Unequal sharing of a common placenta may lead to selective intrauterine growth restriction of one of the triplets, with possible progression to pain sparing, eventually followed by intrauterine demise

Prenatal ultrasound protocol

The protocol of ultrasound follow up is similar to the one used for monitoring monochorionic twin pregnancies. Starting at approximately 16 weeks, ultrasound examination is performed every two weeks to determine the maximum vertical amniotic fluid pocket for each sac and to assess the bladder of each fetus. Oligohydramnios-polyhydramnios sequence (maximum vertical pocket >8 cm in one amniotic sac and <2 cm in the other) suggests TTTS which was fortunately not observed in this case. There was however a discordance of fetal growth more than 15%, requiring repeated Doppler measurements of umbilical artery, middle cerepal artery, and ductus venosus of all triplets.

Maternal complications

Incidences of cardiac complications due to overload, and also preeclampsia are significant higher in triplet than in singleton pregnancies, which requires close monitoring of the mother. These mothers are also at increased risk of uterine atony and postpartum haemorrhage following delivery, hence preventive measures to avoid these potential complication are necessary. Cesarean section is the preferred mode of delivery in triplet pregnancy as there is high incidence of perinatal and neonatal morbidity and mortality with vaginal route of delivery

Delivery

In our case, lower segment Cesarean section was performed under regional/spinal anaesthesia, triplets were delivered by careful minimal handling and handed over to the three respective neonatal teams in attendance in the operating room. Uterotonics were administered after delivery of all babies. The estimated blood loss was average. Mother made an uneventful recovery and discharged home on third postoperative day. All three babies are making satisfactory progress in neonatal unit and aiming for discharge from hospital soon.

Summary

Preterm delivery is the most common cause of death and morbidity in triplet gestations. This includes iatrogenic preterm delivery by Cesarean section before 32 weeks because of insecurity and concerns about fetal wellbeing. About 70% of triplets are delivered before 32 weeks, with high risk of short- and long term complications like cerebral palsy. In our case, regular detailed sonographic assessment of the triplets, together with excellent maternal fitness and cooperation of the couple, enabled the treating obstetrician Dr. Rizmee to extend the pregnancy to 34.0 weeks, when complications of prematurity are very rare