(THIS PAGE IS CURRENTLY BEING UPDATED – SOME INFORMATION MAY BE INCOMPLETE.)
This page has been around for a long, long time. And while my focus on this blog is now mostly technology, I am still a mom to 2 sets of twins! I remember what it was like to be REALLY, REALLY big and pregnant. I remember what it was like breastfeeding 2 babies at one time, pumping while at work, and wondering if I would EVER sleep again. I have tons of stories of rude curious people insisting that they get a look at the babies while in the mall.
We always get lots of questions about how often twins occur, did we use fertility drugs (yes people are that nosey), do twins run in our families, etc. so I thought I would start this page to answer some questions. 🙂
What are the different types of twins?
The main types of twins that everyone knows and talks about are Identical Twins and Fraternal Twins. What most people don't know is that is goes much deeper than that. There are many different types of identical twins! Here's a great page that shows how even twins in different sacs with different placentas can be identical. It also has great info on fraternal twins.
How often do twins occur?
The frequency of twins depends on the type of twins. Identical twins occur about once in every 250 births around the world. This type of twin formation appears to be uninfluenced by age, race, heredity, number of pregnancies or medications taken for infertility (fertility drugs). The incidence of fraternal twins is influenced by race, heredity, maternal age, the number of previous pregnancies and the use of fertility drugs.
The frequency of multiple fetuses varies significantly among different races. Twins occur in 1 out of every 100 pregnancies in white women compared to 1 out of every 79 pregnancies in black women. Certain areas of Africa have an incredibly high frequency of twins. In some places, twins occur once in every 20 births! The occurrence of twins among Asians is less common: about 1 in every 150 births.
Heredity also plays a part in the occurrence of twins. In one study of fraternal twins, the chance of a female twin giving birth to a set of twins herself was about 1 in 58 births.
You are having your 2nd set of twins, what are the chances of repeat twinning?
As of 2011 the chance of having twins your first time around is 16.9 per 1,000 However, once you have one set of twins, you are about five times more likely to repeat twinning with the next pregnancy than would be true in the general population.
You've had twins before. Lightning can and does strike twice! If you've already given birth to a set of twins, look out — you're significantly more likely to do so again. – WhattoExpect.com