Having two babies at a time is associated with a longer life, according to a new study. But that's not because doubling up on dirty diapers increases life span; instead, moms of twins are physically stronger in the first place.
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.
They're also more likely to have health problems later in life, like high blood pressure. More than half of twins and nearly all higher order multiples weigh less than they should at birth.
Analysis shows that twins have lower mortality rates for both sexes throughout their lifetimes.
Since identical twins share the same DNA, the children of two pairs of identical twins are legally cousins, but genetically more similar to siblings.
For a given pregnancy, the odds of conceiving fraternal twins are only determined by the mother's genetics, not the father's. Fraternal twins happen when two eggs are simultaneously fertilised instead of just one.
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.
At age 7, the mean IQ score of twins was 5.3 points lower than that of singletons in the same family, and at age 9, the score was 6.0 points lower. The lower intelligence of twins in childhood may partly be a consequence of the reduced fetal growth and shorter gestations of twins, say the authors.
Using the family-based adult sample, no differences in IQ scores were found between twins and their singleton siblings.
Longer lives
When analyzing the data by gender, the researchers found that female identical twins lived, on average, about 63.4 years, whereas female fraternal twins lived about 61.4 years and the general Danish female population lived about 58.8 years, Sharrow said.
The hardest thing about having twins is…
“Managing the movement of two babies. Carrying them both up and down the stairs, getting them into the car, etc.” —Simeon R. “Often having to make one baby wait!” —Catharine D. “Being outnumbered—the logistics of two on one is definitely the hardest.
A big reason for all those twins is an increase in medically assisted reproduction, including in vitro fertilization, ovarian stimulation and artificial insemination. Another reason is that women in many countries are having babies at older ages.
Most twins are born healthy. A twin pregnancy can mean a higher chance of health complications so you'll need extra check-ups. Twins that share a placenta or inner sac need to be checked more closely. It's good to know whether twins are fraternal or identical for health reasons later in life.
May 24 (UPI) -- According to research published on Tuesday, mothers who give birth to twins are more lucky than they are biologically unique -- a conclusion that goes against previous research done on the issue.
Measures included actigraphy, sleep diaries, and standardized instruments for fatigue, sleep quality, and depression. According to the results, by the time the twins reached full-term, mothers were sleeping an average of 5.4 hours in a 24-hour period, with over 70 percent reporting less than six hours of sleep.
The longest interval between the birth of twins is 90 days, in the case of Molly and Benjamin West, dizygotic (fraternal) twins born in Baltimore, Maryland, USA to parents Lesa and David West (all USA) on 1 January and 30 March 1996.
It's a common misconception that twins skip a generation in families. There is absolutely no evidence, other than circumstantial, that twins are more likely to occur every other generation.
Twins and other multiple-birth individuals can suffer from much deeper and troubling loneliness than single-born individuals. Separation anxiety, which often begins at birth, is the underlying cause of loneliness for twins.
However the researchers looked at it, first-borns had, on average, an IQ of 1.5 points higher than second-born siblings, who in turn had a 1.5 higher IQ than third-borns and so on.
Twins provide a valuable source of information for health and psychological research, as their unique relationship allows researchers to pull apart and examine genetic and environmental influences. Twin study findings have been influential in detecting and treating various diseases and psychological disorders.
The notion that twins always skip a generation is also a myth. The illusion may have arisen because men who inherit the gene from their mothers are unaffected by it ( they do not ovulate), but can still pass it on to their daughters, who, in turn, will have an increased likelihood of conceiving twins.
“For every 1,000 twin pregnancies, around two will have at least one baby with Down syndrome,” Trapane told TODAY Parents. “However, the chance prior to a pregnancy that the pregnancy will be twins and that both twins will have Down syndrome is around one in 1 to 5 million.”
The Science of Fraternal Twins. Mixed-gender twins are the most common type of fraternals, some 50 percent are boy-girl.
Dizygotic twins are the most common type and are known as fraternal twins. Two-thirds of all sets of twins are dizygotic. When two eggs are fertilized during the same pregnancy, the result is a set of dizygotic twins. They are fertilized by two different sperm.
Polar twins. Polar twins share the same chromosomes from their birthing parent, but they get different chromosomes from their non-birthing parent. This is because they're created from a single egg but two separate sperm.