There's one guarantee with pregnancy - you'll have a bump that will grow every week. And if you're carrying twins (or more) that bump is going to expand a lot quicker and you're likely to get a lot bigger.
Your belly may grow bigger, and you may gain more weight, sooner.
In general, women carrying twins are more likely to “show” sooner than those with a single pregnancy.
While many moms-to-be first start to show at about 22 to 28 weeks, those with multiples will probably announce their pregnancy to the world by as early as 20 weeks. Plus more from The Bump: What's the chance of having twins?
Physical Differences Between Singleton and Twin Pregnancies
One can say that a twin belly will be 20% larger than a single pregnancy belly. Sometimes, mothers won't even notice that they're carrying twins, regardless of the size of their bellies.
A twin pregnancy causes the body to produce higher levels of pregnancy hormones, particularly human chorionic gonadotropin (HCG). This may intensify early pregnancy symptoms. Some potential signs of a twin pregnancy include: weight gain, especially in early pregnancy.
You won't know for sure if you're carrying twins until you have an ultrasound, but there may be a few early signs. Some telltale early signs that you may be carrying twins include more severe morning sickness, extreme breast tenderness, or gaining weight more quickly.
Showing earlier than normal. Mothers who are pregnant with twins tend to look pregnant earlier than those who are carrying one baby. So instead of the uterus lifting up and out of the pelvis after 12 weeks or so, it tends to grow much faster.
The two embryos implant in the lining of your uterus, and develop into two fetuses in your uterus at the same time.
A little more than half of twin pregnancies end in preterm delivery (before 37 weeks). 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).
They conclude, “In terms of short- and long-term outcomes, uncomplicated twin pregnancies should not be delivered before 37 completed weeks of gestation and that there is a limited benefit of prolonging pregnancy after that.”
It's a good idea to leave a period for rest and relaxation at the end of your pregnancy, and most people who've experienced this recommend stopping work at some time between 28 and 30 weeks.
The symptoms of twin pregnancies are similar to a singleton pregnancy, but there are some notable differences. You may experience more nausea or fatigue and notice some additional symptoms that singleton pregnancies don't typically present.
If you get a positive test, especially a really dark positive, days before your period is even due, that may be one of the early signs of twins!
Superfetation is a rare event that involves getting pregnant a second time while you're already pregnant. It's so uncommon that cases of superfetation often make headlines. Your body does a good job preventing subsequent pregnancies once an embryo is developing inside your uterus.
If you are carrying twins or multiples, your uterus will start growing and stretching sooner. Your OB/GYN will be able to feel your uterus by touching your belly.
Your nausea and vomiting may be worse than ever: Morning sickness peaks around 9 or 10 weeks of pregnancy for many women. That's when levels of the pregnancy hormone human chorionic gonadotropin (hCG) are highest (morning sickness is thought to be linked to rises in hCG and estrogen).
Short women or women with shorter torsos may show earlier or have a larger-looking bump, because they have less space for the baby to fill, lengthwise. Your baby is positioned in your uterus in a way that maximizes your bump. You're having twins or multiples. You've gained extra weight during pregnancy.
If you test yourself even earlier than that, it's just as likely that what you measured is simply a normal variation in hormone production. Early positives may mean you have two more babies on the way (which research indicates is more common among women over the age of 35), or they may mean that you have just one.
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.
As of 2003, there are on average around 16 sets of twins born per 1,000 births in the United States. It is estimated that 1 in 250 natural pregnancies will naturally result in twins.
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.
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.
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.
You Have Exaggerated Symptoms
1 It might not come as a surprise that the presence of two babies exacerbates these symptoms. Some pregnant moms of multiples report intensified symptoms of nausea, fatigue, breast tenderness, food cravings, or the like.