Women are more likely to conceive fraternal twins once they reach their 30s as a result of an evolutionary response to combat declining embryo viability, according to a new international collaboration involving researchers at UWA.
6.9 percent in women age 35 to 37. 6.8 percent in women age 38 to 40. 5.1 percent in women age 41 to 42. 5.9 percent in women age 43 and above.
According to the Office on Women's Health , women who are aged 30 years or older are more likely to conceive twins. The reason for this is that women of this age are more likely than younger women to release more than one egg during their reproductive cycle.
Family history – Twins tend to be more common in some families. There may be an underlying genetic factor that predisposes a woman to release more than one egg at a time, which increases the chance of having twins.
The chances decrease with age (unlike natural twin conception), as women 38 to 40 only have a 5.3 percent rate of twins. And for those who are 43 and older, the rate is just 0.5 percent .
However, for a given pregnancy, only the mother's genetics matter. Fraternal twins happen when two eggs are simultaneously fertilized instead of just one. A father's genes can't make a woman release two eggs.
Everyone has the same chance of having identical twins: about 1 in 250. Identical twins do not run in families. But there are some factors that make having non-identical twins more likely: non-identical twins are more common in some ethnic groups, with the highest rate among Nigerians and the lowest among Japanese.
A big reason for all those twins is an increase in medically assisted reproduction, including in vitro fertilization, ovarian stimulation and artificial insemination. Another reason is that women in many countries are having babies at older ages.
Multiple pregnancy usually happens when more than one egg is fertilized. It also can happen when one egg is fertilized and then splits into 2 or more embryos that grow into 2 or more babies. When one fertilized egg splits into 2, the babies are called identical twins.
There have been some small studies that suggest folic acid may increase the likelihood of conceiving multiples. But there aren't any large-scale studies to confirm that this increases your chances for multiples. If you are trying to get pregnant, taking folic acid will help protect your baby's brain development.
Several factors for causes of embryo splitting were suggested, including maternal age, prolonged embryo culture, ovarian stimulation, and zona pellucida (ZP) manipulation [6].
For women born 1870-1899, moms of twins averaged reproductive spans of 14 years 11 months versus 14 years for singleton moms. Both results were statistically significant. Moms of twins also were older at the time of their last birth.
After age 35, there's a higher risk of pregnancy-related complications that might lead to a C-section delivery. The risk of chromosomal conditions is higher. Babies born to older mothers have a higher risk of certain chromosomal conditions, such as Down syndrome. The risk of pregnancy loss is higher.
Like you, more women than ever before are having babies later in life. But as an older mom-to be, you may be concerned about the increased risk for problems during pregnancy. Rest assured, most healthy women from age 35 on into their 40s have healthy babies. So try not to focus on your age.
Many people believe twins skip a generation, but that's just a myth. The idea that twins skip generations likely comes from the fact that the genetic factors contributing to twins only come from the gestational parent's side.
Fraternal twins result when two different eggs are fertilized, each by a different sperm cell. This can happen when a woman produces several eggs (most often two) at the same time. This is called hyperovulation. Fraternal twins don't share the same DNA.
Monozygotic (MZ) twins, also called identical twins, occur when a single egg cell is fertilized by a single sperm cell. The resulting zygote splits into two very early in development, leading to the formation of two separate embryos.
Race – African-American women are more likely to have twins than any other race. Asian and Native Americans have the lowest twinning rates. Caucasian women, especially those over age 35, have the highest rate of higher-order multiple births (triplets or more).
Having two babies at a time is associated with a longer life, according to a new study. But that's not because doubling up on dirty diapers increases life span; instead, moms of twins are physically stronger in the first place.
Yes, some types of twins are hereditary, meaning that twins run in families. Heredity on the mother's side ups a couple's odds of conceiving fraternal twins. Fraternal twins are two babies from two different eggs that were released from the ovaries simultaneously.
Identical Twins and Genetics
Although theories and research abound, there is no established connection between genetics and monozygotic (identical) twinning.4 Scientists haven't really identified a clear cause for monozygotic twinning, which occurs when a fertilized egg splits and develops into two (or more) embryos.
Hyperovulation-stimulating foods: There are a few foods that naturally increase the rate of ovulation and stimulate ovaries to release multiple eggs. Such hyperovulation stimulating foods include cassava (an African wild yam or sweet potato), tofu, soy isoflavones, whole grains, and whole wheat.
Identical twins have 100% of their DNA the same while fraternal twins share only 50%. But what about semi-identical twins? Well, they have 75% of their DNA the same.
When I tell patients there's about a 50/50 chance for either sex, I also tell them the father's genes determine the baby's sex since some of his sperm carries X chromosomes and some carries Y chromosomes. That's with the assumption, though, that the man's sperm carries equal numbers of X and Y chromosomes.