Not long after I’d announced that I was pregnant for the first time, friends began offloading their pregnancy and childbirth books on me. I don’t know if their motivation was to free up space on their shelves or to help prepare me for a life-changing event, but it felt like my job to get through the pile of advice. As I tried to figure out how to be a mother to the unknowable being growing inside of me, I needed all the help I could get.

I’m far from the first expectant parent to search for direction within the pages of a pregnancy advice book. The original What to Expect When You’re Expectings were called midwifery manuals. “To conceive with child is the earnest desire if not of all, yet of most women,” wrote Jane Sharp, midwife and author of The Midwives Book, or, the Whole Art of Midwifry Discovered, first published in 1671. Historical scholar Victoria Glover borrowed Sharp’s observation as the title of her recent study, which analyzes 26 of these midwifery manuals published across nearly 300 years. It’s a fascinating view into changing attitudes and practices around pregnancy and childbirth when obstetrics was transforming itself from informed guesswork into something resembling science.

Midwifery manuals were the product of three major cultural forces intersecting with women’s health: the Renaissance, the scientific revolution, and the printing press. For Glover, the manuals are a lens to understand how the intellectual, religious, and scientific currents of the time influenced women’s lives. For us, they’re a reminder to be grateful for modern medicine.

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First, who read these books? “They were owned by middle-class or wealthy people,” Glover says. “While there was a great growth of literacy in England in the mid-1600s, there were still a lot of people who couldn’t read. Some of the manuals were geared towards physicians or midwives, versus the women who were pregnant.” At the time, only one in three women in England were literate. But the books had staying power: One popular manual, titled The Birth of Mankind, went through 13 editions in 200 years.

Today, pregnancy advice still travels the same trickle-down route from research to changing norms among the general population of mothers. But hundreds of years ago, women’s bodies were astoundingly misunderstood. At the beginning of the 16th century, it was widely believed that women had the same reproductive organs as men—but on the inside. This “one-sex theory” came from Galen, the most famous physician of the Roman Empire. Galen lived in the second century, and his writings were considered the Western bible of medicine for over a thousand years. Galen believed gender was based on heat: Men were warm, and women were cold. Therefore, if a woman got too hot—say, from exercising too much—her genitals could fall outside of her body and turn her into a man.

Galen’s writings had been based on the assumption that animal anatomy was the same as humans’. But during the Renaissance, physicians challenged restrictive religious attitudes about human dissection and started to examine the insides of their own species. It was clear that mistakes had been made.

Not all of the misapprehensions about pregnancy reflected in midwifery manuals were necessarily bad, from a woman’s perspective. Glover writes that most manuals advised would-be parents to make sure there was pleasure and love during sex. Owing to Galen’s one-sex theory, the authors believed that if “a man required an orgasm to release his seed, and if men and women were anatomically identical, then a woman must also experience an orgasm in order to release her seed.” Unfortunately, the books stopped short of offering actual sex tips, “with authors merely stating the need for the proper arousal of both partners as well as the quality of the love making in the spirit, mind, and body.”

When I was hoping to conceive for the second time, a friend recommended a book she said held the secret to influencing the baby’s gender. This is a very old idea. Again looking back to Galen’s gender theory, it was believed that the right side of the body was warmer and conducive to the “warmer” gender: males. The left side was colder and thus female. At the time, women’s bodies were believed to vary in temperature throughout their reproductive cycles. (That’s true: Today, women track their ovulation through small changes in temperature.) In the early modern era, it was thought that heat transferred from the right to the left side of the womb. Following that logic, you could choose your baby’s gender in one critical moment.

According to two separate manuals published in 1684 and 1702, Glover writes, “in order to conceive a male child, the woman should lay on her right side after intercourse in order that the seed may fall to the right side of the womb. To conceive a female child, the author instructed that the woman should lay on her left side so that the seed may fall to the left side of the womb.” If this technique hadn’t been proven to work—say, if a wife had borne only daughters, and a son was greatly desired—there was a more draconian method. “One of the manuals said, if you want a boy, tie off the man’s left testicle so seed can’t come out of that one. Therefore, seed will only come out of the right testicle and you’ll get a boy,” Glover told me.

But did people actually do that? We can’t be certain, but it’s possible. “I feel like considering this Galenic idea of body heat was so prevalent, people would say, ‘Maybe it’s weird, but we’ll try it,’ ” Glover said.

As it is today, not being able to conceive was a major problem. “Barrenness” was considered a temporary condition, caused in part by mysterious forces like God’s displeasure or maybe witchcraft. There were actually laws in England outlawing the use of witchcraft to affect a couple’s fertility. Only six of the 40 manuals in Glover’s study seriously discuss barrenness by enchantment, but they do suggest cures that it certainly couldn’t hurt to try. “The most popular of these remedies was for the husband to urinate through his wife’s wedding ring without letting a drop run outside of it,” Glover writes. Another involved the husband drinking water that had been dropped from a horse’s mouth.

Modern women pee on a stick that tells us if we’re pregnant. Women in the early modern era also looked to their urine for signs of conception, but in a different way. Thomas Chamberlayne, author of The Compleat Midwife’s Practice Enlarged, suggested peeing into a jar and waiting three days. Then, the woman should strain the pee through linen cloth. If she could see “living things” in the urine, baby might be on the way! But she wouldn’t truly know if she was pregnant until she felt the “quickening,” a movement in her stomach—around four or five months.

It was widely debated, though, how long her pregnancy would last. Some physicians argued that a full term could be as short as seven months or as long as 11. This might have been deliberate ignorance—to cover up premarital relations or claim an heir for a dead husband. Pierre Dionis, author of A General Treatise of Midwifery, advised physicians and midwives: “The Reputation or Honour of these Women is at stake; and there for the Surgeon, for the Peace and Credit of Families, must not only pretend to be convinc’d of the possibility of them, but likewise bring parallel cases to illustrate and prove it.”

When it came to making it through the pregnancy, advice to early modern mothers was as variable as I found in my own books. Authors disagreed with one another about what to eat and what to avoid, how much to sleep, when it was safe to exercise (if at all), and so on. The biggest differences? Today’s guides don’t tend to recommend amulets or necklaces, and early modern guides included a lot of advice about riding in coaches, now sadly irrelevant.

As Glover studied the manuals through multiple printings over the years, she could see growing skepticism around long-held beliefs. For example, one author dismissed the oft-repeated idea that if a pregnant woman drank a lot of red wine, her baby would be covered in red splotches, or birthmarks. He wrote that his own brother was born with splotches because his mother had smallpox during pregnancy.

“But at the same time, there was a story I came across in several manuals about a woman who gave birth to 300 babies in one go,” says Glover. “It’s like, how could anybody think this is possible? But it kept appearing in the manuals. I don’t know if it’s trying to cater to people’s older beliefs, or if they actually believed it. Unfortunately, we don’t have somebody going, ‘I read this today, and it’s total crap.’ ”

In my own experience, I quickly learned to filter my stack of pregnancy books through my own attitudes and beliefs. So maybe some moms of the early modern era would have been willing to take the chance on a glass of red wine once in a while (probably advisable, given the quality of their drinking water), but followed advice to the letter on how to prepare their birthing rooms. The stakes were high. During the period when the manuals were published, the maternal mortality rate roller-coasted from nine deaths out of every 1,000 mothers up to nearly 16 and back down to seven. Pregnant women were advised to get their affairs in order, in case they didn’t make it through childbirth.

Things have gotten better for aspiring and pregnant mothers in almost every way since early modern times. I’m pregnant with my second child now, and I’m not worried that my child is going to be born covered in hair because I looked at a picture of a saint wearing camel’s-hair clothing. I never thought that I might be carrying a boy because I was acting less “peevishly” than I would if I was having a girl. And I’ll never be tempted to drink wine with a few drops of my own menstrual blood to aid in my recovery after birth.

But even as science has made pregnancy infinitely more understood, there’s still so much we don’t know. I can imagine that my experience isn’t fundamentally different from that of the women who read the midwifery manuals. I still get prescriptive yet conflicting advice from books, well-meaning but disturbing anecdotes from friends and relatives, and, ultimately, that strange feeling of being so intimately connected to someone I haven’t yet met.