It is estimated that 1 in 250 natural pregnancies will naturally result in twins. While twin pregnancies can happen by chance, there are some factors that may increase your odds of having two babies at the same time.
In Australia, twins happen in 1 in every 80 births. This means that 1 in 40 Australians is a twin.
In the United States, twins account for about 3 percent of live births.
If you're 30 or older, you're more likely than younger people to release more than one egg during a menstrual cycle. You have relatives who have had multiples. If you or other people in your family have had fraternal twins, you may be more likely to have twins, too.
However, few genes appear to be definitively linked to hyperovulation, so it could just be that genetics in general on the mother's side contribute to the probability of having fraternal twins. Heredity on the father's side, on the other hand, does not increase a couple's odds of having twins.
This belief is based on the assumption that twinning is genetic and runs in families. However, if that was truly the case—if there was a twin gene—then twins would occur with predictable frequency in those families that carry the gene. There is no concrete scientific evidence that suggests twins skip a generation.
Just over 3 percent of babies in the United States are now born in sets of two, three or more, with the majority — about 97 percent — of these multiple births being twins. So your chance of having twins is about 3 in 100.
According to the Centers for Disease Control and Prevention (CDC) , twin births have nearly doubled over the last 40 years. A woman has a higher chance of having twins if she conceives with the assistance of fertility treatment or is aged 35 years or over.
Fraternal twins, which are the more common type of twins, occur when more than one egg is released, fertilized and implanted in the uterus. In other words, fraternal twins are formed from two separate eggs and two separate sperm.
A twin pregnancy can often be detected in your first trimester by an ultrasound Opens a new window at 6 weeks or later. If your healthcare provider checks your hcG levels, a higher-than-normal level can be a sign of a twin pregnancy. But you'll need an ultrasound to confirm that it's really twins.
And because the death rate in the womb is higher for twins than for singleton births, female twins are more common than male twins.
The study of 381 pairs of identical twins and two sets of identical triplets found that only 38 were genetically identical, Tina Hesman Saey reports for Science News. Most had just a few points of genetic mismatch, but 39 had more than 100 differences in their DNA.
Identical twins are almost always the same sex, although there are some rare exceptions to this rule. Because identical twins occur when a single fertilized egg splits and forms two embryos, each embryo has the same chromosomes (usually, XX for girls or XY for boys). Remember that sex and gender are not the same.
Yes, some types of twins run in families. Non-identical (fraternal) twins tend to be hereditary.
Twin births account for approximately 3 percent of live births in the United States. Barring pregnancies that result from assisted reproductive technology, dizygotic twins are far more common than monozygotic twins and account for 70 percent of all twin gestations.
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.
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“Having twins is not twice as hard—it's exponentially more difficult,” says Natalie Diaz, author of What To Do When You're Having Two and CEO of Twiniversity, a global support network for parents of twins.
The birth process is similar to giving birth to a single baby. If you're planning a vaginal birth, your health team may recommend that you have an epidural for pain relief.
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.
It shows it's possible to release two… or even three eggs during ovulation. Another 2006 study used ultrasounds on 507 women over one to three cycles. They found that nearly 21% of women had multiple ovulations for at least one cycle.
Fetal movement in more than one area. Fundal height is greater than gestational age. The baby bump is measuring larger than expected. Gaining weight quickly.
A third milestone in a twin pregnancy is 32 weeks to 34 weeks. Babies born then generally have an excellent chance of survival, without any major long-term complications, though they might not have full lung maturity and will need to spend time in the NICU.
The biological phenomenon of giving birth to twins with two different biological fathers is called heteropaternal superfecundation. This happens when a second ova released during the menstrual cycle is fertilised by sperm cells of a different man from separate sexual intercourse.
If you've always dreamed of having a big family, the thought of having twins might be appealing. But your chance of having twins is pretty low – twin births are just 3.2 percent of births in the United States.
If one identical twin has autism spectrum disorder (ASD), the other twin has a 76 percent chance of also being diagnosed with it. The numbers are lower for fraternal twins.