Multiple pregnancy involves carrying two or more babies simultaneously. This form of gestation presents distinct considerations for both the expectant parent and the developing fetuses. While relatively uncommon, accounting for approximately 3 in 100 births, the rate of multiple births has seen an increase in recent decades. Understanding these pregnancies, from their origins to their management, offers valuable insights.
What Are Multiple Pregnancies?
Multiple pregnancies are categorized by how the embryos form. Identical (monozygotic) multiples result from a single fertilized egg that splits into two or more embryos. These babies are genetically identical, always the same sex, and share a common placenta in approximately 60-70% of cases, though each usually has a separate amniotic sac.
Fraternal (dizygotic) multiples, conversely, develop from two or more separate eggs, each fertilized by a different sperm. These babies are genetically distinct, similar to other siblings, and can be the same or different sexes. Each fraternal multiple has its own placenta and amniotic sac. Chorionicity (number of placentas) and amnionicity (number of amniotic sacs) describe multiple pregnancies, impacting their management and potential complications. Dizygotic twins are almost always dichorionic-diamniotic. Monozygotic twins can be dichorionic-diamniotic, monochorionic-diamniotic (one placenta, two sacs), or rarely, monochorionic-monoamniotic (one placenta, one sac), depending on when the single fertilized egg divides.
Factors Increasing the Likelihood of Multiples
Several factors can increase the chances of conceiving multiples. A family history of fraternal twins, particularly on the mother’s side, suggests a genetic predisposition. Additionally, maternal age plays a role, with individuals over 30 having a greater likelihood of multiple pregnancies. This is partly because older individuals may produce more eggs in a single cycle.
Assisted Reproductive Technologies (ART), such as in vitro fertilization (IVF), contribute to the rising rate of multiple births. During IVF, multiple embryos may be transferred to increase the chance of successful implantation, raising the possibility of conceiving twins or higher-order multiples. Ovulation-stimulating medications, often used in ART, stimulate the ovaries to produce multiple eggs, increasing the likelihood of multiple pregnancies.
Managing a Multiple Pregnancy
Managing a multiple pregnancy involves more intensive prenatal care compared to a singleton pregnancy. Frequent prenatal visits are recommended to closely monitor the growth and health of all fetuses, as well as the expectant parent’s well-being. Regular ultrasound scans are a standard part of care to track fetal development, assess fluid levels, and detect any complications early.
Individuals carrying multiples have increased nutritional requirements, needing additional calories, protein, and iron to support the growth of multiple babies and prevent maternal anemia. For example, women carrying twins may need an extra 300-500 calories per day. It is also recommended that women carrying twins with a normal body mass index gain between 37 and 54 pounds.
Multiple pregnancies carry a higher risk for complications, including preterm labor, preeclampsia (high blood pressure during pregnancy), and gestational diabetes. Preterm birth is common, with the median gestational age for twins being just under 36 weeks and for triplets around 31-32 weeks. Activity modifications or bed rest may be advised to reduce the risk of preterm labor, though preventive bed rest has not consistently shown to prevent preterm birth.
Delivery and Postpartum for Multiples
Delivery of multiples involves specific considerations, with options including vaginal birth or C-section. The decision depends on factors such as the number of babies, their positions, and their health. For twins, a vaginal delivery may be possible if the first baby is positioned head-down. Approximately 40% of twin mothers deliver via C-section, and a combination of vaginal and C-section delivery may occur.
The postpartum period after a multiple birth often requires extended recovery. The body undergoes significant changes to accommodate multiple fetuses, and healing can take longer than after a singleton birth. Physical recovery from a C-section, a major abdominal surgery, can take six to eight weeks, while vaginal birth recovery may involve soreness and bleeding for several weeks.
Caring for more than one newborn presents challenges. Fatigue is common due to increased demands for feeding and care. Around 40% of multiples require neonatal care after birth, which can extend the hospital stay. Establishing a strong support network and utilizing twin-friendly products can help ease the transition into early parenthood with multiple infants.