The New York Times reported this month that expectant mothers are taking up marijuana in increasing numbers. We asked women who used marijuana during pregnancy to share their stories.

Hundreds of readers wrote in; most had smoked, while a few vaped or ate marijuana-laced edibles. Roughly half said they had used pot for a medical reason. Most felt marijuana use had not affected their children, or were not sure; just a handful worried the children might have suffered cognitive deficits.

The Times followed up with a few of these women in greater depth. Where they wished to protect their privacy or avoid legal consequences, only first names are used.

Margaret, 38

Formerly worked in advertising, New Jersey

With her first pregnancy, Margaret was “super-nervous about everything,” she said. She drank only decaf coffee, skipped sushi and cold cuts, and ate mostly organic food.

During her last two pregnancies, however, she was nauseated around the clock, so she turned to marijuana.

Her doctor had prescribed Zofran, which is used off-label for nausea in pregnancy. She took it a few times, but didn’t want to take it every day. “To me, it seemed unnatural,” said Margaret. “Marijuana is a plant.”

At that point, her nausea was so debilitating she couldn’t eat, touch food or even prepare it — not an ideal situation with children in her charge. “A few puffs of a joint would allow me to function,” she said. “It was not like I was toking up and eating Doritos.”

Her husband, who doesn’t use pot, fretted that it could harm their growing baby. She searched online for information about pot use in pregnancy and wasn’t worried by the studies she found. Eventually they came to an agreement.

“If we had to choose between Zofran and weed, we’d definitely choose weed,” she said.

Pot use in pregnancy has been associated with lower birth weights and cognitive issues later in a child’s life, but in the end all three children had “very healthy birth weights,” Margaret said, and no noticeable adverse effects.

Her doctors did not know about her marijuana use. Margaret had read articles about women getting a call from child protection services because they had used in pregnancy.

A self-described “minivan-driving suburban mom,” she never gave doctors a reason to test her. “This is my white privilege talking, but I really didn’t think it could happen to me,” she said.

Claire, 32

Social worker, Oregon

There are a few reasons Claire vapes marijuana, and they are the same regardless of whether she’s pregnant: headache, cramps, nausea or, she said, “if I’m in a terrible, terrible mood, really impatient and irritable.”

Expecting her first child, Claire vaped once a week in her third trimester. But with her second child on the way, she took a puff or two every other day then went weeks without. She vapes because she doesn’t get as stoned as she might with a joint, she said.

Claire, who has two children younger than 5, is skeptical of Big Pharma. “I have been called a hippie before,” she said, adding that she has an “aversion to prescription medicine.”

While pregnant, she lived in Oregon, where pot is legal, and in another state where it’s not. In neither place did she tell her midwife about her marijuana use.

“Stigma is the only reason,” she said. “Just anywhere, people don’t like pregnant women to smoke pot.”

But Claire did check the internet for research on marijuana’s potential harm to developing fetuses. She found a small study done in Jamaica that had tracked pot-smoking mothers-to-be who didn’t use tobacco or drink alcohol.

The researchers found that infants exposed in the womb to THC — marijuana’s main psychoactive ingredient — were more alert and better able to regulate themselves at 30 days old than babies whose mothers had not used marijuana.

She took its findings with a grain of salt, but admitted that the study comforted her. “It was a little bit of wind beneath my sails,” she said.

Claire found other studies of pregnant women who smoked tobacco or drank alcohol, but very few involving women who were expecting and used pot exclusively, like her. She wishes there were more.

“The group I’m in of lefty hippie professional women, it’s definitely only marijuana,” Claire said. “No one is drinking or smoking tobacco in pregnancy. They are being very careful.” She thinks the federal government demonizes pot, but in her circles “there’s a lot of trust in marijuana.”

Diana Donath, 50

Gymnastics coach, Texas

Ms. Donath, a lifelong Texan, started smoking marijuana as a teenager. As a young expectant mother, she kept smoking joints through two pregnancies.

“I really don’t care what people think,” said Ms. Donath. “I’m 50, and those two kids have graduated college.”

Research has shown that THC — tetrahydrocannabinol — can cross the placenta to reach the fetus, potentially harming brain development and reducing birth weight. But Ms. Donath saw no ill effects in cannabis use.

Neither newborn had a low birth weight; actually, one was 10 pounds. And, she added, “both of my kids have above-average intelligence.”

Unlike many 20-something mothers-to-be, Ms. Donath was straight with her doctors: “I have never not been honest with my doctors about everything I do.”

Her ob-gyn was concerned about whether she smoked cigarettes or drank alcohol, but he never told her to quit marijuana. “Since it hasn’t been studied that much, I can’t advise you one way or another,” she recalls him saying.

Even though she has no regrets, Ms. Donath said, if her ob-gyn had said marijuana was bad for her baby, she would have stopped using it. But at the time, she thought “it’s my lungs, not my child’s.”

Still, a 1988 study published in The New England Journal of Medicine found that smoking cannabis can reduce blood’s ability to carry oxygen, which in theory could affect the fetus.

Jane, 41

Pharmaceutical researcher, New York

When Jane was pregnant with the last of her three children, she was in a stressful marriage, suffering through nausea, and having contractions much too early. She took a calcium channel blocker and got progesterone injections to relax the contractions and postpone the birth.

She started using pot to quell her nausea and cope with the stress. “I would occasionally take a puff to not be bedridden and worried about contracting all day long,” she said.

As a drug-company researcher, Jane did not smoke pot flippantly. First, she searched PubMed, a database of scientific studies, then she considered the risks and benefits.

“Knowing how little I was doing of it, it was worth the benefit of maintaining the pregnancy,” she concluded. Her doctor had prescribed Zofran for morning sickness, and she figured “marijuana can’t be any worse.”

In the end, Jane’s daughter was born healthy at 37 weeks. Today, “there’s nothing wrong with her but her sassy attitude,” Jane said. “She’s my smartest.”

Jane never talked about using marijuana, even with her ob-gyn, who was a friend. “If you smoke pot in pregnancy, that’s not to be discussed,” she said, describing herself as a high-functioning working professional who is studying for a Ph.D.

“It’s not a matter for public consumption.”

Tycia, 24

Stay-at-home mother, Colorado

Tycia uses pot for pain relief from a back injury she sustained at the age of 12 but she is not a registered medical-marijuana patient. She vapes a couple of times a day, and did so even when she was pregnant with her daughter, Lilith.

“I definitely didn’t smoke for the first trimester,” she said. “I was trying to live as healthy of a lifestyle as I possibly could.”

She used tiger balm ointment and Advil to manage her back discomfort. She had taken opioids in the past, but was worried about getting addicted, having her baby be dependent, and being constipated.

In the second trimester, though, she went back to pot after her nausea grew unbearable. “She was growing, and I was still very nauseous and practically unable to eat anything,” Tycia said. “I tried. I just couldn’t do it.”

She was terrified of telling doctors about her decision, so she weighed the risks and benefits on her own. She also tried to stop smoking cigarettes. “I made quite an effort to quit,” she said. It didn’t work: “I couldn’t get rid of two or three cigarettes.”

Today her daughter seems completely normal. “Maybe I’m desensitized, but I think she’s just fine,” Tycia said.

She breast-feeds Lilith and hopes to continue that as long as possible. Asked if she worries that marijuana’s main psychoactive ingredient has been found in breast milk, she replied, “The responsible person in me wants to say, ‘Yes, I am very concerned.’ But honestly, no.”

Marijuana is natural, she said, and “just about everyone I know smokes or uses it in some form, so I feel it’s O.K.”