The idea of having multiple babies at the same time at first might sound tantalizing. One grueling nine-month period and voilà: You're on your way to synchronized play dates and kids helping each other with homework. The reality is, if you birth multiples, meaning you house more than one baby in your womb, you are less likely to end up appearing on TV and scoring a book deal than you are to end up grappling with complex health issues that last a lifetime. It's worth it, then, to take a look at how multiple births occur, and how having one can affect a family in the short term and over time.
How are multiple pregnancies conceived?
Only 2 percent of multiples are conceived naturally, says William Schoolcraft, M.D., founder and medical director of the Colorado Center for Reproductive Medicine, a Denver fertility clinic widely regarded as one of the best in the world. When we think of a multiple birth, most of us think of in vitro fertilization, but the majority of multiple births, especially those with triplets or higher, are the result of injecting fertility drugs, says Schoolcraft.
In vitro offers a physician more control over how many eggs are implanted in a woman's womb. Clomid, a fertility drug taken orally, increases the likelihood of a twin pregnancy. A pregnancy with triplets, quadruplets, or more is usually the result of injected fertility drugs, along with sexual intercourse or artificial insemination.
"With injected fertility drugs, you can get lots of eggs, perhaps 10 eggs or more, and you really don't have control of how many eggs are produced," says Schoolcraft. "You can look and think you see three or four follicles, but there may be a couple more hiding. [They're] easy to miss." Because of this margin of error, many physicians steer clear of injecting fertility drugs, and instead use Clomid or in vitro. "More and more, doctors are shying away from these injectable drug treatments," says Schoolcraft.
Are multiple births regulated?
While no laws exist in the U.S. to dictate the occupancy limits of a woman's womb, the American Society of Reproductive Medicine has established clear guidelines by which reputable clinics and physicians abide. If a doctor is a member of ASRM, then he or she agrees to follow these standards. The standards are age-based and determined by the likelihood of successful embryo implantation. (The older you are, the more likely it is that you will need to try with more embryos to result in a viable pregnancy.) The ASRM recommends:
"So with a 33-year old, you are going to be more careful, because her chance of keeping all embryos [is] greater," says Schoolcraft. "At the age of 41, twins, or more, are uncommon even with the transfer of multiple embryos."
It's a numbers game, and no one can be sure of the outcome. "We have to balance the desire to get pregnant against the risk of multiples, and at the same time we have to make adjustments for age," says Schoolcraft. "Our goal is to avoid triplets at all cost. We try to avoid twins, but the [health] risk [faced by] twins isn't nearly as great."
The ASRM guidelines used to recommend that physicians implant more embryos. That was until 1998, when Schoolcraft's clinic pioneered a method of in vitro fertilization called blastocyst transfer. Using this technique, doctors are able to grow embryos in a petri dish for five days, a longer period of time than had been previously possible. After the five-day time period, it's easier to identify which embryos are most viable, allowing a higher success rate of implantation—thereby lowering the need to implant more embryos than ideally wanted by the mother.
A focus on one healthy embryo
"Most researchers focus on identifying ways to access the best embryo, so we can make one viable pregnancy. We're getting close to the day where we can just put back one embryo and have success."
A woman in the U.S. would receive more than the regulated amount of implanted embryos only if her physician identified a special need. "Rarely, exceptions are made," says Schoolcraft. "You have to make a note in the chart, explaining what are the medical circumstances justifying this altered judgment."
"An octuplet scenario is extreme," says Schoolcraft.
Worldwide, in vitro standards differ from those in the U.S. "In Europe, there are many countries where the government pays for in vitro, and because they pay for it, they can regulate it." In many European countries, the governments allow a physician to implant only one embryo at a time, therefore the pregnancy success rates from in vitro are lower in Europe than in the U.S., says Schoolcraft. In more developing countries, where technology is less sophisticated and there are fewer regulations, physicians are implanting more embryos than what is recommended in the U.S., he says.
What are the health risks for multiple babies?
The ASRM establishes guideline for embryo implantation because the risk factors for multiples are concerning. The biggest risk factor for multiple babies is premature birth, which is defined as one that occurs before 37 weeks' gestation. The average gestation for a single birth baby is 40 weeks; the average gestation for twins is 35 weeks. For triplets, it's 33 weeks, and for quadruplets, the average gestation is 29 weeks. "There is a big risk for premature birth, and the risk goes up the more babies that are inside," says Schoolcraft. "The more premature the babies are, the more complications they suffer."
One issue is nutrition while in utero. Multiple babies and multiple placentas compete for nutrients from the mom, says Schoolcraft. "They can be undernourished, compared to babies who have a uterus all to themselves."
Premature babies are also more likely to have the following health problems, according to the March of Dimes:
Preterm birth is also the leading cause of death in the first month of life.
Sometimes, additional health problems surface later in life, says Schoolcraft. "This is what is behind these guidelines from the American Society of Reproductive Medicine," says Schoolcraft. "Clearly, most physicians in our field would consider triplets a complication to be avoided if at all possible."
What are the health risks for the mother?
And what about the mother? Not that any moms get much attention after the birth of their child, whether one or many. But having multiples does take an exponential toll. Any nutrient depletion the mother may undergo, due to her body's prioritizing the nutrients she eats and stores in her body to be diverted to her babies, can be made up after birth, says Schoolcraft.
However, a mother carrying multiples has an increased risk of the following complications during her pregnancy:
She also, obviously, has an increased chance in having a C-section, especially if pregnant with more than two babies.
She's also at higher risk for postpartum complications, including:
This last one is, once again, a numbers game. Any parent knows it would clearly be easier to secure and ride an elephant through the streets of New York, than to try and coordinate the nighttime sleep habits of two or more newborns.
Can multiples be emotionally healthy?
It can be tough attending to every little need of a baby, yet interaction with a primary-care provider is integral for a child's emotional development. In fact, some theories suggest that close attention to your child's needs during the first year of life, especially between six to 12 months, is a sound start to his or her emotional well-being.
Studies have shown that multiples are at risk for receiving less of this critical caregiver attention, despite a parent's best efforts. One study published in the Journal of Advanced Nursing in December 2001 found that twins and triplets received less individual attention than single infants. Though parents in this study were capable and had proficient childcaring strategies in place, they simply were unable to provide the same level of care. Their multiple children were talked to, held, and looked at less, and left alone more often, than the children of parents who'd birthed one child at a time.
Preemie babies also are at risk for lack of human touch and attention. Though, according to information from the Hospital for Sick Children in Toronto, Canada, any deficiencies that develop during a preemie's stay in the hospital—when incubators and medical equipment can prevent a preemie from being held—can be made up through adequate parental attention within the subsequent two years. If a parent has enough resources in place to offer the right attention and care, it's possible to develop a strong attachment bond.
The book Preemies (Pocket, 2000), co-authored by neonatologist Mia Wechsler Doron, M.D, and Dana Wechsler Linden and Emma Trenti Paroli (both parents of preemies), states that if, for some reason, the child does not receive enough loving care for a long period of time, he or she can develop failure to thrive, a disorder in which a child doesn't grow normally. There's also the risk of developing attachment disorder. Children with attachment disorder are unable to form trusting affectionate relationships and are unable to comfort themselves.
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