The idea of having twins tends to polarise people. Some couples say they’d love the chance to parent two babies and others react in an entirely different way. If you are a twin or have twin siblings then your concept of the reality is likely to be very different to someone who’s never had anything to do with more than one baby at a time.
Are twins common?
Many reproductive experts believe that as humans we probably have more twin pregnancies than any of us are aware of. Technological advances have found that it is reasonably common for there to be more than one embryo conceived and implanted, but of these, only one is viable and survives.
How do twins happen?
If you are keen to increase your chances of conceiving two babies then it’s important to understand how twins are made.
There are two types of twins; identical and non-identical. Identical or monozygotic twins are formed when one egg is fertilized by one sperm which then divides into two separate embryos. Each shares exactly the same genetic components and identical genetic structures. Identical twins also share a placenta.
Non-identical or dizygotic twins form from two separate eggs being fertilised by two separate sperm. These twins are their own unique little individuals and share no more genetic composition than siblings with the same parents. Each baby in a non-identical twin pair will have its own placenta.
Another name for non-identical twins is fraternal; the other name for identical twins is non-fraternal.
What about twins in families?
Twins do run in families. But the genetic predisposition for having twins only applies to the mother. It is her family history which influences the chances of her having hyper ovulation.
Any woman can have identical twins and family history does not play a role with these.
What are the odds of having twins?
Currently in Australia 1.6% of all pregnancies result in multiple births and of these, 98% are twins. Naturally conceived twins occur once in around every eighty nine births. The majority of twins who are born are non identical and a result of two eggs being fertilised.
Some fraternal twins look very similar; others share some resemblance whilst the remainder may not even look the slightest bit related.
What will help boost my chances of having twins?
- Being older rather than younger helps. It seems to be a twist of nature that just before a woman enters peri-menopause, her ovaries start releasing more than one egg each month. This “fertility spike” is also influenced by a surge of oestrogen. Fertility research has proven that twin pregnancies are much more common in women who are over 35 years. But this only applies to non-identical twins.
- Have fertility assistance such as in vitro fertilisation or take fertility drugs. These stimulate the ovaries to support more than one ovarian follicle each month towards maturity. The result is that more than one egg is released.
- Pick your own genetics carefully! Though we all know this is impossible. But if you come from a family where non-identical twins are common then your family history and genetic endowment means that you’ve got a greater chance of having them yourself. But identical twins can occur in any family.
- Be of African/American heritage. Women from this ethnic background have a distinctly higher rate of twin pregnancies.
- Having been pregnant before. Women who have previously had a baby or two have a higher chance of conceiving with twins.
- Have a big family. This theory is based on pure maths; the more times you conceive the greater the likelihood of conceiving more than one baby.
- Get pregnant while you are on the pill. Difficult as this can be overall, there is a higher incidence of women conceiving with twins when they are on oral contraceptives.
- Try to conceive straight after you have stopped taking the pill. The theory is that for the first couple of cycles the woman’s body is going through a hormonal readjustment phase.
- Already have a set of twins. Because the likelihood of conceiving with twins again is higher in women who’ve already had them.
- Be heavier rather than lighter so that you’ve got a higher body mass index (BMI). Some researchers claim that a woman with a BMI of greater than 30 boosts her chances. But considering a healthy range during the fertile years is 20-25 and 30 would put you into the overweight/obese category then this is not a healthy recommendation.
- Taller women tend to conceive more twins. But there is nothing you can do about your height, other than blame your parents!
- Take a folic acid supplement before you conceive. The general recommendation for women who are planning to conceive is to start taking folic acid supplements one month before conception.
- Encourage your partner to eat some oysters. The urban myth about oysters being an aphrodisiac is not entirely without basis. Oysters are high in zinc and this helps with sperm production. The more healthy and mobile his sperm are, the greater the likelihood of being able to fertilise an egg or two. If he’s keen to take supplements, the recommendation for men in their fertile years is 14mg/day. Green leafy vegetables, cereals, bread, seeds and wheat germ are all excellent sources of zinc.
- Be a twin yourself. Mothers who are twins are more likely to have twin babies. There is no influence on the male partner’s side, only the mother’s. But it does seem that fathers may pass the twin gene onto their daughters for their future conception possibilities.
- Eat more yams/sweet potatoes. It is a fact that more women conceive with twins who live in areas where yams are a major component of their diet. It seems that a naturally occurring chemical component of the yams helps to support ovarian function.
- Keep breastfeeding your older baby or toddler. Women who are producing prolactin and breastfeeding are more likely to conceive with twins. Though some women do not resume regular ovulation and menstrual cycles for the entire time they are breastfeeding; this is very individual.
What’s fact and what’s fiction when having twins?
- The idea that conceiving twins skips a generation is not true. Although there can appear to be a pattern in some families of this happening, the odds of having identical twins is the same for every woman.
- Eating a diet which is high in dairy foods, milk and meat is said to help, especially at the time of ovulation. But there is no scientific evidence to support this.
- Alternative therapies do not increase the likelihood. There is no scientific evidence to support the theory that accupuncture, naturopathy, aromatherapy, chiropractic or flower essences increase the likelihood of having twins.
Last Published* December, 2022
*Please note that the published date may not be the same as the date that the content was created and that information above may have changed since.