The sound of my 10-week-old baby-to-be's heartbeat filled the room, caroming off the walls, as percussive as a marching band. The nurse practitioner who'd strapped the fetal monitor to my belly smiled. "Wow, that child is already so strong," she said. "The next few months of your life are going to be very interesting." I didn't pay much attention. I was too enraptured with this raucous new life sparking inside me — the first science project I had ever, to my knowledge, performed correctly. But I soon discovered the truth in my nurse's veiled warning. The next 6 months were plenty interesting. I experienced elation, despair, indigestion, fluctuating blood sugar, and a mad craving for pineapple juice — not to mention the vomiting. It was the loveliest and most disagreeable time of my life.
Pregnancy can make a woman glow. But it also can give her acne and make her sick, exhausted, crabby, or worse. It's distressingly common for pregnant women to develop severe conditions such as high blood pressure or diabetes, resulting in some 10 million injuries and 529,000 deaths worldwide annually, according to the World Health Organization. Gestation and labor are, frankly, hard work — which is perhaps why nature saw fit to apportion the task to females.
In the mid-19th century, most doctors believed that human babies came ready-made — that every human egg contained a tiny infant that, like a sea monkey, would unfold and grow when exposed to the right ingredients. Of course, back then people also thought raw meat spawned maggots through spontaneous generation. Thankfully, our understanding of reproduction has progressed a bit. The union of a woman's egg and a man's sperm, each containing only one DNA strand, produces a human embryo. The two strands join and the resulting cell, called a zygote, possesses a full set of genes, half from each parent. The zygote divides into two cells, then four, then eight, and so on, until the full-fledged embryo burrows into the womb.
Doctors used to take a Hallmark view of pregnancy. They considered it a harmonious process, with the baby as the passive recipient of gentle nurturing from Mom. Today, emerging facts about fetal genetics reveal that baby-making is actually a rather harsh contest. It's a battle between the agendas of the fetus, its mother, and — not to be forgotten — the father, whose genes are also in there, squabbling and scheming away. "Pregnancy may be the most intimate relationship in all of nature," says evolutionary biologist David Haig, Ph.D., of Harvard University. "But it is not one body, one flesh." All the issues, in fact, that keep family therapists in business — greed, selfishness, misunderstandings, furtive alliances — start at conception.
Remember Alien? Okay, it's a stretch, but not as big a one as we might like to think. Every pregnancy brings together two beings, with different DNA, who must share a single body for 9 months. Practically from day one, the fetus sends damaging substances into its mother in an effort to increase its own nutrition and blood supply. The mom protects herself by shutting down some of the fetus's more assertive genes — akind of genetic time-out — and by releasing proteins that help her hoard nutrients. This struggle spawns many of the complications of pregnancy — from morning sickness to more severe conditions like high blood pressure. The mother's genes want a healthy baby, but they also want her to stay fit enough to have more children. The baby's genes couldn't care less about brothers and sisters. They say: Gimme gimme gimme. It's a mix, Dr. Haig says, "of cooperation and exploitation."
But there's good news in all this for anyone who's considering joining the baby-making fray. Research is pointing the way to better diagnostic tests for monitoring the health of mother and child. And knowledge is power. The more you know about what's going on in your body during the prizefight that is pregnancy, the better equipped you'll be to make sure no one comes out a loser.