20 Astonishing (and Shocking) Truths About Pregnancy

Creating a new life involves numerous unexpected experiences, such as a condition known as “lightning crotch,” vanishing belly buttons, unforeseen bodily functions, and much more. Discover intriguing, captivating, and sometimes alarming facts about pregnancy.

1. Expectant individuals may encounter “lightning crotch” ...

Pregnancy brings a variety of discomforts, including back pain and contractions. Another challenge is “lightning crotch,” a term for sudden, intense pelvic pain. This sensation doesn’t indicate the onset of labor and is typically harmless. It’s believed to result from the baby’s position in the womb. As the baby descends in the final trimester, increased pressure on the cervix and uterine nerves can cause this sharp pain. 

2. … and the infamous “ring of fire.”

It’s important to distinguish lightning crotch from the “ring of fire,” a term describing the intense burning sensation felt as the baby’s head emerges during delivery. 

3. Just 4 percent of babies arrive on their predicted due date.

A typical human pregnancy spans approximately 280 days, or 40 weeks. Medical professionals determine the stage of pregnancy by counting from the first day of the individual’s last menstrual cycle. Therefore, being 30 weeks pregnant indicates 30 weeks since the last period began, not since conception occurred. 

The notion that a baby will arrive precisely during the 40th week is often inaccurate. In the 1800s, Frederich Naegele, an obstetrician, devised a formula to estimate due dates based on menstrual cycles. The method is straightforward: subtract three months from the last menstrual period’s start date, then add one year and seven days. This places the due date around 40 weeks from the last period. However, Naegele’s rule has a significant flaw: it assumes ovulation occurs on the 14th day of a consistent 28-day cycle. In reality, menstrual cycles vary between 23 to 35 days, and even with a 28-day cycle, ovulation timing can fluctuate. 

Despite this, due dates remain relevant—more than 90 percent of babies are born within two weeks of their estimated due dates.

3. Conceiving is possible for individuals in their forties, fifties, and even later.

Individuals who ovulate are generally most fertile from their late teens to late twenties, with fertility remaining relatively strong into their early thirties. Risks rise after 35, and pregnancies in those 35 years or older are classified as “advanced maternal age” (formerly termed “geriatric pregnancy”). However, this doesn’t rule out the possibility of conceiving in one’s late thirties, forties, or beyond. 

4. A woman delivered a baby at the age of 59.

In 1997, Dawn Brooke, a British woman, achieved a world record by giving birth at 59. She remains the oldest person known to conceive naturally without medical assistance (though she was on hormone replacement therapy at the time). 

5. Another woman utilized IVF to conceive at 74. 

Brooke isn’t the oldest person to give birth: In 2019, a woman gained global attention after giving birth at 74 through in vitro fertilization. 

6. A woman carried nine fetuses during her pregnancy.

In May 2021, Halima Cisse gave birth to nine babies. For much of her pregnancy, she had no idea she was carrying nonuplets. Initially, doctors believed there were seven fetuses, but a specialist clinic in March 2021 revealed two more. Cisse delivered all nine babies via C-section at 30 weeks, and remarkably, all survived. The nonuplets—four boys and five girls—stayed in Morocco for 19 months before returning to Mali.

7. Pregnancy can alter the shape of your belly button.

As the fetus grows, it stretches the abdominal muscles, which can cause the belly button to “pop” or appear to disappear entirely. Transitioning from an innie to an outie is usually painless, though some may experience mild irritation as the outie rubs against clothing. The belly button typically returns to its original shape a few months after delivery.

8. A dark vertical line may appear on the stomach during pregnancy.

Along with a transformed belly button, some individuals may observe a dark line running vertically down their abdomen, known as the linea nigra or “black line.” Everyone has a linea alba, a connective tissue band separating the left and right sides of the rectus abdominis. This line is especially noticeable in individuals with well-defined abs. During pregnancy, hormonal changes cause this tissue to darken, forming the linea nigra.

9. Morning sickness isn’t limited to mornings.

Morning sickness, characterized by nausea and vomiting during pregnancy, is inaccurately named, as it can occur at any time of day. Approximately 70 percent of pregnant individuals experience this condition. It typically begins within the first month and persists through the first trimester, though some may endure it throughout their entire pregnancy. The exact cause remains unclear, but recent studies suggest a hormone called GDF15, which may have evolved to induce food aversion in response to toxins. While generally mild, severe cases are diagnosed as hyperemesis gravidarum, a condition experienced by Kate Middleton, the Princess of Wales, during her three pregnancies.

10. Pregnancy involves the creation of an entirely new organ.

During pregnancy, individuals not only nurture a fetus but also develop an entirely new organ. Known historically as “afterbirth,” the placenta forms inside the uterus and is delivered after the baby. This organ is vital, as 20 percent of the pregnant person’s blood flows through it to nourish the fetus. The placenta supplies nutrients and oxygen while removing waste from the fetus’s blood. It’s also substantial in size, typically measuring around 10 inches long and 1 inch thick by the time of delivery. 

11. Some individuals consume their placentas postpartum.

Certain people eat their placentas, believing it offers health benefits like increased energy and milk production. However, there’s no solid scientific evidence supporting these claims. Experts, including those at the Mayo Clinic, caution against placenta consumption due to the risk of bacterial infections.

12. By the end of pregnancy, the uterus can weigh approximately 2 pounds.

A non-pregnant uterus is typically likened to the size of a lemon. However, by the end of pregnancy, it grows to resemble a watermelon and weighs approximately 2 pounds. 

13. Internal organs shift positions during pregnancy.

The uterus’s growth necessitates significant internal reorganization. It presses downward on the bladder, increasing the frequency of urination, and upward on the stomach and intestines, leading to heartburn and reduced meal capacity. In the final trimester, lung compression can cause shortness of breath. Thankfully, these organs usually return to their original positions within months after delivery. 

14. Pregnancy can lead to pelvic separation.

During pregnancy, the body produces high levels of relaxin, a hormone that loosens joints and ligaments to prepare for childbirth. However, this can sometimes lead to symphysis pubis dysfunction, where the pubic symphysis—the joint connecting the pelvic bones—separates. While not dangerous, this condition can cause significant pain. 

15. Pregnancy reshapes the brain ...

Pregnancy also impacts the brain, particularly the gray matter—the tissue essential for daily functions. It shrinks in areas responsible for processing social cues. A 2016 study suggests this change enhances the brain’s efficiency in responding to a baby’s needs, making it more specialized. These brain changes persist for at least two years, outlasting many other pregnancy-related symptoms.

16. … and other bodily transformations.

Pregnancy can lead to lasting changes beyond the brain. Hormonal shifts may alter hair texture, turning straight hair curly or the reverse. Additionally, some individuals may find themselves needing a new shoe size as pregnancy can flatten and widen their feet.

17. Fetal cells integrate into the parent’s body.

While pregnancy lasts nine months, traces of the fetus remain in the parent indefinitely, creating what some call “genetic chimeras.” Fetal cells migrate from the placenta into the parent’s body, circulating and embedding in tissues and organs, where they persist long after birth.

18. Fetal cells may pose risks—or offer benefits.

Those wandering fetal cells can sometimes cause issues, such as autoimmune disorders and preeclampsia, a dangerous pregnancy-related blood pressure condition. However, they might also have benefits, like potentially protecting against breast cancer, heart attacks, and aiding in wound healing—though evidence remains inconsistent and limited.

19. A pregnant person’s body recognizes the fetus as non-foreign tissue.

While the body typically rejects foreign tissue, requiring transplant patients to take immune-suppressing drugs, this doesn’t happen during pregnancy. Once the embryo implants in the uterus, it deactivates genes in the decidua—the uterine lining—that would normally trigger an immune response against foreign tissue.

20. Pooping (and peeing) during labor is common.

Here’s a less-discussed fact about childbirth: Many people poop during labor. It’s a natural and frequent occurrence. 

It’s logical for this to happen: the muscles involved in bowel movements are the same ones used during labor. The baby’s position also plays a role—if the baby is face-up rather than face-down in the birth canal, their body exerts more pressure on the parent’s intestines, often triggering a bowel movement. 

While pooping during labor might seem embarrassing or uncomfortable, it can benefit the newborn by exposing them to fecal bacteria, which may improve their gut microbiome. Babies delivered via C-section miss out on this exposure, potentially increasing their risk of immune-related issues later in life. A 2020 study even proposed mixing a small amount of the birthing parent’s fecal matter into breast milk to enhance a C-section baby’s microbiome—though this should never be attempted at home due to the risk of harmful bacteria.

If an IV is used for fluids during labor, frequent urination is likely. Additionally, if an epidural prevents the person from urinating independently, a nurse may need to use a catheter to empty the bladder, as a full bladder can obstruct the baby’s passage through the birth canal.