Introduction
Pregnancy with more than one baby is a joyful and exciting time for many couples. However, it also comes with increased risks for complications. High-order multiple pregnancies, where there are three or more babies, are quite rare, occurring in only one to seven out of every 10,000 pregnancies. Nigeria has the highest incidence of multiple births in the world, including high-order births. Multiple pregnancies are on the rise globally and are linked to higher risks for the mother. These risks include spontaneous miscarriages, preterm labor, early leakage of amniotic fluid, hypertensive disorders during pregnancy, the need for cesarean section, as well as bleeding before and after childbirth.
What Is High-Order Multiple Pregnancy?
The occurrence of multiple births has become much more prevalent in modern times compared to the past. According to the United States (US) Department of Health and Human Services, the rate of twin births has risen by more than 75 percent since 1980, while the rate of triplet, quadruplet, and high-order multiple births has increased even more significantly. This increase can be attributed, in part, to the growing number of women undergoing infertility treatment, which carries a higher risk of multiple pregnancies.
Additionally, more women are now choosing to delay pregnancy until later in life, and older women have a higher likelihood of conceiving multiples, especially with the assistance of fertility treatments. Despite advancements in medical technology that have improved the outcomes of multiple births, it is important to note that these pregnancies still pose significant medical risks and complications for both the mother and the children involved.
What Are the Causes of High-Order Multiple Pregnancy?
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Recent studies have shown that the main reason for triplet and quadruplet pregnancies is the use of human menopausal gonadotropin (hMG) therapy. To reduce the occurrence of high-order multiple pregnancies caused by hMG, serial ovarian ultrasound evaluation was introduced in the mid-1970s. To understand how advancements in technology have affected the causes of high-order multiple pregnancies, several studies were done.
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Of all the pregnancies studied, 20 percent occurred naturally, 73 percent were associated with ovulation induction, and seven percent occurred during an IVF cycle. Among the pregnancies associated with ovulation induction, nine (82 percent) were linked to Clomiphene therapy, while only two (18 percent) were linked to hMG therapy. Currently, hMG therapy is no longer the primary cause of triplet and quadruplet pregnancies.
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It is possible that the monitoring of hMG cycles through serial serum estradiol and ovarian ultrasound has contributed to the decrease in hMG-induced high-order multiple pregnancies observed.
What Are the Complications Associated With High-Order Multiple Pregnancy?
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Premature Birth: A majority of higher-order multiples and more than 60 percent of twins are preterm (born before 37 weeks). The chance of an early birth increases with the number of babies in the pregnancy. Babies born prematurely have not fully developed bodies and organ systems. These babies may require assistance breathing, feeding, fighting infection, and remaining warm because they are frequently small and have low birth weights (those under 2,500 grams or 5.5 pounds). Particularly at risk are newborns born before 28 weeks of pregnancy or very premature babies. Most of their organs might not be developed enough to operate properly and might not be prepared for life outside of the mother's uterus. Neonatal intensive care unit (NICU) care will be required for a large number of multiple-birth newborns.
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Gestational Hypertension: Pregnant women carrying more than one fetus are over twice as likely to experience elevated blood pressure. Compared to a single-child pregnancy, this condition frequently manifests earlier and is more severe. Additionally, it may raise the risk of placental abruption or the placenta's premature separation.
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Abnormal Levels of Amniotic Fluid: Abnormalities in the levels of amniotic fluid are frequently observed in pregnancies involving multiples, particularly in cases where twins share a placenta.
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Bleeding After Giving Birth: In multiple pregnancies, the mother is at risk for bleeding following delivery because of the enormous placental area and overdistended uterus.
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Birth Defects: Multiple birth infants are at a significantly higher risk, approximately double, of being born with congenital abnormalities. These abnormalities can include neural tube defects like spina bifida, gastrointestinal issues, and heart abnormalities.
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Intrauterine Growth Restriction: Intrauterine growth restriction (IUGR) is when an unborn baby is estimated to weigh less than expected for their gestational age. This is determined through a growth ultrasound and is considered IUGR if the estimated weight falls below the 10th percentile on standardized charts for singleton babies. Multiples are more likely to experience IUGR due to placental crowding, resulting in one or all of the babies being smaller than expected. While most cases of IUGR are mild and do not cause complications, in some cases, it can lead to preterm delivery with complications for newborns. The earlier the delivery, the higher the risk of complications. If pregnancy is affected by growth restriction, then the mother will need to have more frequent hospital visits and undergo antenatal testing to monitor the well-being of the babies. Antenatal testing involves ultrasound and external electronic fetal heart rate monitoring and is done in the late third trimester of pregnancy.
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Twin-To-Twin Transfusion Syndrome (TTTS): TTTS is a condition that happens in identical twins who share a placenta. Blood vessels in the placenta connect and transfer blood from one twin to the other. This occurs in around 15 percent of twins who have a shared placenta. In TTTS, one twin receives more blood than the other through the blood vessel connections in the shared placenta. As a result, the recipient twin may have an overloaded cardiovascular system and excessive amniotic fluid. On the other hand, the smaller twin, known as the donor twin, does not receive enough blood and has low levels of amniotic fluid.
Conclusion
High-order multiples are becoming more common due to assisted reproductive technologies and pose a significant risk during pregnancy. The care for high-order multiples should involve educating about preventing preterm birth, regularly monitoring maternal symptoms and cervical status, adjusting activities based on individual needs, focusing on maternal nutrition, using ultrasound to assess fetal development, and anticipating any potential maternal complications.
