Quite a good article here on the remarkable medical advances with respect to the uterus, as well as looking at past ideas (artificial wombs, or "in-vitro gestation") that no longer look viable.
This section is particularly interesting:
Since Liu’s mouse experiments, the medical community has more or less abandoned in-vitro gestation. The past decade saw a renaissance in transplant technology, and advances in the burgeoning field of human prenatal epigenetics have rendered gestation outside a mother’s body a less plausible concept. Scientists are learning more about the interplay between fetal
development and the mother’s whole body—not just her uterus.
“The fetus gets an advantage by developing within a maternal body,” says Janet DiPietro, associate dean for research at the Johns Hopkins Bloomberg School of Public Health. DiPietro oversees the Johns Hopkins Fetal-Development Project, a 20-year endeavor that tracks how
physiological aspects of the maternal-fetal bond shape development. DiPietro told me that everything from a mother’s circadian rhythms to her posture sends cues to the growing fetus.
“The maternal voice is heard very well, which probably sensitizes the baby to the sounds of their own language. Amniotic fluid develops the odor of certain foods that women eat, and so there’s a notion that cultural likes and dislikes are transmitted to the fetus via the amniotic fluid,” she says, “So the maternal context provides an environment that goes far beyond the direct circulatory-system connection.”
DiPietro explains that in the future, an artificial-uterus transplant is “far, far more likely” than in-vitro gestation, in part because the placenta, which grows from the uterus after implantation, is “one of the most enigmatic organs that we have.” Scientists can’t understand it, let alone construct it from scratch. The complex interplay between the placenta—which grows from the fetus’s own cells—and the mother’s blood flow, immune system, and circulating oxygen has been so poorly researched that Alan Guttmacher, director of the National Institute of
Child Health and Human Development, recently called it “the least-understood human organ.” But with a bioengineered uterus, the assumption is that if you get the uterus right, a placenta,
amazingly, will grow on its own once the transplant recipient becomes pregnant.