To form identical or monozygotic twins, one fertilised egg (ovum) splits and develops into two babies with exactly the same genetic information. To form fraternal or dizygotic twins, two eggs (ova) are fertilised by two sperm and produce two genetically unique children.
Factors that increase the chance of twins include: consuming high amounts of dairy foods, being over the age of 30, and conceiving while breastfeeding. Many fertility drugs including Clomid, Gonal-F, and Follistim also increase the odds of a twin pregnancy.
Although certain factors increase the chance of having twins, there is no way to improve the odds of having twins naturally. A woman will usually find out that she is pregnant with twins from an ultrasound early on in the pregnancy.
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.
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.
This is why fraternal twins run in families. However, only women ovulate. So, the mother's genes control this and the fathers don't. This is why having a background of twins in the family matters only if it is on the mother's side.
For a given pregnancy, the odds of conceiving fraternal twins are only determined by the mother's genetics, not the father's.
As you age, your chance of conceiving twins increases. Researchers have found that women over 35 produce more follicle stimulating hormone (FSH) than younger women, which may cause more than one egg to drop at ovulation.
Taking fertility medication is one of the most common ways to get pregnant with twins. They increase fertility by stimulating egg production. If more eggs are produced, the chances that more than one egg will be released during ovulation also increase.
Foods naturally rich in folic acid like avocado, spinach, broccoli, liver, and legumes also have the tendency to increase one's chances of conceiving twins. According to a study, consuming extra folic acid while trying to get pregnant can raise the chance of giving birth to twins slightly higher.
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.
Older women generally have a higher chance of conceiving twins. A 35 year old woman is about 4 times more likely to have fraternal twins than a 15 year old! That is because they are experiencing some hormonal changes as they near menopause. This could encourage their body to release more than one egg during ovulation.
While 40 weeks is the full gestation period of the average pregnancy, most twin pregnancies are delivered at approximately 36 weeks (range 32-38 weeks depending on the type of twin pregnancy).
Being pregnant with multiples doesn't necessarily mean that your pregnancy will be problematic. However, women carrying multiples do have a higher chance of developing complications such as high blood pressure and preterm labor. For this reason, all multiple pregnancies are considered high-risk.
In a twin pregnancy, there are elevated levels of hCG, making it possible to have a very early positive result. However, home pregnancy tests won't confirm if twins are present, only the presence of hCG. It takes around 2 weeks after conception for hCG to be detected in a hCG pregnancy test.
With a twin pregnancy, your body makes high levels of pregnancy hormones. So morning sickness may come on earlier and stronger than if you were carrying a single baby. You may also have earlier and more intense symptoms from pregnancy, like swelling, heartburn, leg cramps, bladder discomfort, and sleep problems.
The mother gives an X chromosome to the child. The father may contribute an X or a Y. The chromosome from the father determines if the baby is born as male or female.
The quick answer to this question is that, in a twin pregnancy, it is the mother's genes that determine twins. First up, giving birth to identical twins is not genetic, but conceiving fraternal twins is. The mother may have the genetic trait of releasing two eggs in one menstrual cycle.
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.
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.
Although this is quite rare it can happen and it's called superfetation. Two babies are conceived from separate acts in two different cycles. These babies can be from the same father or two different men. When heteropaternal superfecundation occurs, the babies are from different fathers.
They found that twins at first birth were linked to higher divorce rates at 13.7% compared to 12.7% for singletons. The link was statistically higher among moms attending college at 14.4% with twins vs. 10.5% with single births.
Monoamniotic-monochorionic Twins
These types of twins share a chorion, placenta, and an amniotic sac. This is the rarest type of twin, and it means a riskier pregnancy as the babies can get tangled in their own umbilical cords.
While men can carry the gene and pass it on to their daughters, a family history of twins doesn't make them any more likely to have twins themselves. 3 But, if a father passes on the "twin gene" to his daughter, then she may have a higher chance than normal of having fraternal twins.