First babies are less likely to be “on time” at 39 weeks, and more likely to be a little late, between 41 and 43 weeks. Among full-term pregnancies, first babies are born about 1.3 days later on average.
Babies that come early or before 37 weeks are more likely to be first babies. According to the data recorded in the National Survey of Family Growth, around 12% of first babies are premature, compared with 10% of other babies.
The researchers found that 50% of all women giving birth for the first time gave birth by 40 weeks and 5 days, while 75% gave birth by 41 weeks and 2 days.
WASHINGTON -- Boys are slightly more likely to be born premature than girls, and they tend to fare worse, too, says a new report on the health of the world's newborns. "This is a double whammy for boys," said Dr. Joy Lawn of the London School of Hygiene & Tropical Medicine, who led the team of researchers.
The average length of human gestation is 280 days, or 40 weeks, from the first day of the woman's last menstrual period.
Rabin said there is no known biological reason why firstborn babies would be more likely to be early or late. After 42 weeks of pregnancy, a baby is considered overdue, Rabin said, and doctors become concerned about complications, such as an aging placenta that is not able to deliver proper nutrition to the baby.
More than 90% are born two weeks either side of the predicted date. But, as noted above, only 4% (or 4.4%, ignoring pregnancies with complications etc) are born on the predicted date itself - in other words, the chance of this happening is less than one in 20.
These three risk factors make you most likely to have preterm labor and give birth early: You've had a premature baby in the past. You're pregnant with multiples (twins, triplets or more). You have problems with your uterus or cervix now or you've had them in the past.
If you have any of these signs or symptoms before your 37th week of pregnancy, you may be experiencing preterm labor: Change in your vaginal discharge (watery, mucus or bloody) or more vaginal discharge than usual. Pressure in your pelvis or lower belly, like your baby is pushing down. Constant low, dull backache.
Boys are more likely to be born before their due date. After the 40-week mark, however, the odds slightly favor a girl.
First babies are less likely to be “on time” at 39 weeks, and more likely to be a little late, between 41 and 43 weeks. Among full-term pregnancies, first babies are born about 1.3 days later on average.
In the United States, most births occur between June and early November. Count back nine months, and you'll see that places most conceptions in the fall and winter.
A normal cycle can be between 21 to 35 days, and some people can even have cycles that range outside of that. Regularity isn't that common, so there's a fair chance that the calculation will be off, but the last menstrual period measurement is still used because it's considered fairly reliable most of the time.
Researchers now believe that when a baby is ready for life outside his mother's uterus, his body releases a tiny amount of a substance that signals the mother's hormones to begin labor (Condon, Jeyasuria, Faust, & Mendelson, 2004). In most cases, your labor will begin only when both your body and your baby are ready.
You may start to feel pressure in your vagina or pelvis. “This may be due to 'lightening,' which is when the baby drops down from the abdomen. Some women feel lightening as pelvic pressure or even low back pain,” says Dr. Emery.
In the days before labour starts, you might notice some subtle signs. It can be hard to tell them apart from your normal pregnancy discomforts. You might notice a change in the discharge from your vagina or a few cramps in your abdomen. You may have a low, dull ache in your back that can come and go.
Does baby always drop before you go into labor? Your baby won't necessarily drop before labor begins — whether it's your first pregnancy or a subsequent one. If yours doesn't, don't worry. When or whether baby drops and you experience lightening will have no impact on your labor.
Spending most of your time in bed, especially lying on your back, or sitting up at a small angle, interferes with labor progress: Gravity works against you, and the baby might be more likely to settle into a posterior position. Pain might increase, especially back pain.
Mothers who are 17 or younger or 35 or older are more likely to have a premature baby. Teen moms are more likely to get high blood pressure during pregnancy and less likely to get the health care they need. Older women are more likely to have health problems before they get pregnant.
Where will my near-term baby be cared for after birth? Babies born before 34 weeks go to the Neonatal Intensive Care Unit (NICU). Babies born between 34 and 37 weeks who weigh more than 1,800 grams (about 4 pounds) may be able to go to the Progressive Care Nursery (PCN).
It could be that your uterus size doesn't sync up with the standard growth charts (i.e. you measure big). And if the measurements are off by three weeks or more, in many cases your due date is moved to reflect this.
Only 7.6 percent percent of male babies and 5.5 percent of female babies were in the womb 42 weeks or longer. Males were also 1.5 times more likely to be born at 43 weeks or longer. The researchers noted that the most common reason for prolonged pregnancies is an error in calculating the due date.
The report also showed that the average (or mean) age of mothers for all births rose from 24.6 years to 27.2 over the past three decades. Over one-half of all births still occur to women in their twenties–the peak childbearing years–but the average age in this group has shifted steadily upward since 1970.
It is very common for pregnant women to go beyond their due date. In fact, only about 5 per cent of women actually give birth on the exact date they are due. Most babies arrive between 37 weeks and 41 weeks of pregnancy, but usually within a week either side of their expected due date.