Multiple Pregnancy

Multiple pregnancies occur when two or more ova are fertilized, resulting in dizygotic (non-identical) twins, or when a single fertilized egg divides, resulting in monozygotic (identical) twins. Twins, triplets, and higher-order multiples are all included in the phrase multifetal gestation. Multiple births are on the rise in the United States, accounting for a significant part of infant morbidity and mortality. Furthermore, these pregnancies frequently create a treatment problem for the obstetrician.

Each fetus in dizygotic multiple pregnancies has its own placenta (either distinct or united), amnion, and chorion. The situation is more complicated with monozygotic multiple pregnancies depending on the timing of the ovum division:

In monochorionic twin pregnancies, one twin may receive less blood and grow at a slower rate (twin-twin transfusion). One fetus may die and create a mummified papyraceous fetus or be reabsorbed.

Pregnancies with triplets can be monochorionic, dichorionic, or trichorionic. Chorionicity and animosity in multiple pregnancies alter the risks and thus pregnancy management, and are therefore examined in early scans.

Risk factors

Dizygotic twinning includes:

• Multiple pregnancies in the past.
• Ancestral history (maternal side).
• Maternal age is getting older. Women aged 45 and above are the most likely to have multiple births; in England and Wales, 105.5 out of every 1,000 women giving birth in this age range had multiple births in 2014.
• Origin of the race (more common in women of West African ancestry; less common in those of Japanese ancestry).

Management

Timing of delivery

• Women with uncomplicated monochorionic twin pregnancies should be offered elective birth once a course of prenatal corticosteroids has been recommended.
• Women who are pregnant with dichorionic twins should be offered elective birth beginning at 37 weeks and 0 days.
• Women with triplet pregnancies should be offered elective birth once a course of prenatal corticosteroids has been recommended.

Vaginal delivery of twins

If there are no complicating conditions, the woman can go into spontaneous labor if the first twin is cephalic.

• Cesarean section is preferred when the first twin presents in a breech or transverse position.
• In most situations, vaginal birth occurs normally.
• Check for umbilical cord prolapse if the membranes break.
• Immediately following the birth of the first child:
• A vaginal examination is used to determine the location of the second fetus.
• If the presenting part is engaged (typically after a couple of contractions), burst the second amniotic sac and deliver the baby.
• If the patient is transverse, an external cephalic or internal podalic version may be attempted to move the patient into a longitudinal posture.
• If vaginal inspection confirms success, rupture the second amniotic sac when the fetal head is engaged.
• If everything else fails, have a cesarean section.

Contractions can be reduced after the birth of the first fetus, and if they do not return promptly, and IV oxytocin infusion can be started, after which the birth of the second fetus should be simple. The second twin will normally arrive 20-45 minutes after the first.

If the delivery of the second twin is problematic or if bradycardia develops, a vacuum extraction (in cephalic position) or breech extraction can be utilized to hasten delivery without the need for a cesarean operation.

To avoid postpartum hemorrhage, the third stage should be aggressively treated by intramuscular (IM) injection of Syntometrine or Syntocinon as the fetal head is born.

Operative delivery of twins

The 2011 NICE guidance acknowledges the greater risk for the second twin in simple twin pregnancies at term but states that evidence on whether section for the second twin improves outcome remains equivocal and should not be offered regularly, except as part of a study. Operative delivery is used in the scenarios indicated above, either electively or in an emergency when a vaginal delivery would put one or both twins at risk. It may also be considered if the woman chooses it after being properly informed of all options, risks, and advantages.

References

• www.webmd.com/baby/guide/multiple-pregnancy-twins-or-more-topic-overview
• patient.info/doctor/multiple-pregnancy
• emedicine.medscape.com/article/977234-overview
• kidshealth.org/en/parents/multiple-births.html
• Pathak, Sumita and Sochana Sapkota. A Textbook of Leadership and Management. Bhotahity, Kathmandu: Vidyarthi Pustak Bhandar, 2014
• www.webmd.com › Pregnancy › Guide