Quintuplets refer to five babies born from the same pregnancy. While multiple births are familiar, the simultaneous arrival of five infants is far less common than twins or triplets.
The Rarity of Quintuplet Births
The spontaneous conception of quintuplets is exceptionally rare, estimated to occur in approximately 1 out of every 55 million pregnancies. This contrasts sharply with the frequency of other multiple births: twins occur in about 1 in 83 pregnancies, and triplets in roughly 1 in 6,889 pregnancies.
In the United States, only 24 quintuplets and higher-order multiples were born in 2015. Such pregnancies carry increased risks for both the mother and babies, including preterm labor, low birth weight, and various pregnancy-related complications.
Factors Influencing Quintuplet Occurrence
Quintuplets can arise from spontaneous conception, which is exceedingly uncommon, or more frequently, through assisted reproductive technologies (ART). Naturally conceived quintuplets can result from one to five separate fertilized eggs, or a single fertilized egg that splits multiple times. The Canadian Dionne quintuplets, born in 1934, were an instance of naturally conceived identical quintuplets.
The use of ART has significantly increased the incidence of multiple births, including quintuplets. Fertility drugs, such as Clomid or Pergonal, stimulate the ovaries to release multiple eggs, increasing the chance of several eggs being fertilized. In vitro fertilization (IVF) also contributes to higher-order multiples, particularly when multiple embryos are transferred to improve pregnancy success rates.
Nearly all quintuplet pregnancies today are a result of fertility treatments. These medical interventions aim to overcome infertility, but a side effect can be the development of multiple fetuses.
Historical Trends in Quintuplet Births
The prevalence of multiple births, including quintuplets, increased during the late 20th century, particularly from the 1970s through the late 1990s. This was largely due to the adoption of assisted reproductive technologies, where medical practices often involved transferring several embryos during IVF cycles to maximize pregnancy success.
In recent years, medical practice has shifted to reduce risks associated with high-order multiple pregnancies. Rates of triplets and higher-order births in the United States peaked around 1998 and have since declined. This reduction is largely attributed to the increasing emphasis on single embryo transfer (SET) in IVF.
Medical guidelines now recommend transferring fewer embryos, typically one or two, to lower the incidence of multiples. This strategy aims to achieve a healthy singleton pregnancy, as multiple pregnancies carry increased health risks for both mother and babies.