Pregnancy
Pregnancy is the period of reproduction during which a member of a species (typically, but not always, a female) carries one or more live offspring from implantation  through gestation. As Jean-Luc Picard once succinctly noted of Deanna Troi, "She's pregnant. She's going to have a baby." () 

Obstetrics was the branch of medical science that specialized in the care of lifeforms during pregnancy, childbirth, and the subsequent recovery period following delivery. Those who practiced this form of medicine were known as obstetricians or obstetrics specialists. (; )

Pregnant women often experienced increased hunger. In 2375, at a First Contact Day party, Harry Kim told B'Elanna Torres to leave some food for the other partygoers. She explained that she was "eating for two" (herself and her growing baby). ()

Species variations

Bajorans 
Bajoran females carried their children for less than five months and, because they had a short gestation period, they vascularized very quickly, forming a complex interconnecting network of blood vessels with their children. Bajoran women did not experience nausea during morning sickness like Humans, but were instead prone to uncontrollable fits of sneezing. In 2373, Doctor Bashir attempted to develop a small respirator to alleviate Kira's sneezing. ()

Bajoran women were commonly given Makara herbs in order to maintain their progesterone levels during pregnancy, though the herbs counteracted sedatives such as merfadon. ()

Betazoids 
Female Betazoids carried their young for ten months. Sometimes, when carrying Betazoid babies, Betazoid mothers could telepathically sense the infant's thoughts. (; )

Breen 
Among the Breen, a warlike species, pregnancy at a young age is a common event. ()

Ferengi 
On the planet Ferenginar, pregnancy was considered a rental, and as a lessee, the male Ferengi had certain rights. ()

Humans 
Human females typically carried their children for nine months. Females often suffered from morning sickness and woke up feeling nauseous, though morning sickness usually ended after the first trimester. Additionally, they often gained extra weight and suffered mood swings. Having contractions was not uncommon in the late months of pregnancy. (; )

Klingons 
Klingon females carried their children for thirty weeks, though The Doctor believed that the gestation period for Klingon-Human hybrids would likely be less. The Doctor advised a pregnant B'Elanna Torres to expect mood swings during her pregnancy. ()

Worf stated that a male should have some say in what a pregnant female could and could not do. ()

Ocampa 
Members of the Ocampa species typically become pregnant between the age of four and five. Females carry their young in a pouch on their back called a mitral sac. ()

Scathos 
Among the Scathos species, any woman who conceives a child before her fourth decade is summarily executed. ()

Xindi-Primate 
Anaprolean Fever could cause miscarriage in Xindi-Primate pregnancies. ()

Yridians 
In the Yridian culture, a male that impregnates a female with no intentions of taking responsibility for his actions dishonors the female's family. Yranac claimed that if his sister were ever defiled in such a way, he would do or pay anything to find the person responsible. ()

Male pregnancy 

On Earth, the majority of all pregnancies were carried by female organisms. In 2151, after an encounter with a female Xyrillian, Charles Tucker III became the first recorded Human male to become pregnant (though he was more of a carrier of genetic information than an actual biological parent and never carried the child to term). ()

Xyrillian males usually carried infants to term in a pouch on the upper chest. They served only as hosts, and the offspring only contained genetic material from the mother. Impregnation could occur with only minor physical contact and could be unintentional on the mother's part. Humans and Xyrillians were genetically compatible, as Charles Tucker III discovered when he was impregnated by a Xyrillian female. He also developed a nipple on his wrist. ()

Males of Vilix'pran's species, a winged race from the Alpha or Beta Quadrant, were known to carry their young (referred to as budding). ()

Complications 
There were both routine and serious, even potentially fatal, problems with pregnancy. Ensign Samantha Wildman experienced many difficulties with her pregnancy on board , including shooting pains in the lower back and legs. () 

It was recommended that caffeine intake during pregnancy be limited to avoid complications or negatively affecting infant development. Miles O'Brien had Quark develop a decaffeinated raktajino (which Odo sarcastically referred to as Quarktajino) for a pregnant Kira Nerys, though the beverage ended up being undrinkable. ()

Exposure to hazardous materials during pregnancy was also discouraged. ()

Pregnancies involving a hybrid being could sometimes result in complications. During the delivery of Samantha Wildman's child, its Ktarian ridges lodged in her uterine wall. This threatened to rupture the uterus and cause internal bleeding and possibly death. While the child was safely transported out of Wildman, it did not survive because of a power loss to critical medical equipment. However, the same procedure was performed aboard a duplicate Voyager and was successful, and the infant was brought over before the duplicate Voyager was destroyed. She was given the name Naomi. ()

Becoming ill or injured while pregnant could lead to the loss of the developing child. Degra's wife Naara lost their third child, Trenia, three months into her gestation due to Anaprolean Fever. ()

Alyssa Ogawa lost her and Andrew Powell's baby due to temporal energy de-aging the fetus until its DNA broke down. ()

List of pregnancies 

 Dobara with Nikolai Rozhenko's child. ()
 Ekoria ()
 Eleen with Leonard James Akaar by Akaar ()
 Gracie () 
 Gorn female ()
 Indava ()
 Kathryn Janeway by Tom Paris ()
 Juarez with her baby by Alfredo Juarez ()
 K'Ehleyr with Alexander Rozhenko (; revealed in )
 Kes with Linnis Paris by Tom Paris (alternate timeline; )
 Winona Kirk with James T. Kirk by George Kirk ()
 Kira Nerys with Kirayoshi O'Brien by Miles O'Brien and Keiko O'Brien ( to )
 Lursa of the House of Duras ()
 Mika with her baby by Dukat ()
 Miramanee (died before baby could be born) by James T. Kirk ()
 Nero's wife by Nero (died before baby could be born) ()
 Keiko O'Brien with Molly O'Brien by Miles O'Brien () and ( to )
 Alyssa Ogawa by Andrew Powell ()
  by Gabriel Hwang ()
 Seska with her baby ()
 Spot with her kittens by one of twelve male cats on the  ()
 B'Elanna Torres with Miral Paris by Tom Paris ( to )
 Deanna Troi with Ian Andrew Troi  ()
 Lwaxana Troi by Jeyal ()
 Charles Tucker III by Ah'len ()
 Vilix'pran (budding) ( and )
 Samantha Wildman with Naomi Wildman by Greskrendtregk ( to ; found out in )
 Yanar ()
 Kasidy Yates-Sisko by Benjamin Sisko ( through )
 Kaitlen female worker ()
  with two stillborn babies and one carried successfully to term. ()

Appendices

Background information 
Actresses who have been pregnant while playing roles on Star Trek include Gates McFadden, Roxann Dawson, and Nana Visitor. McFadden's and Dawson's pregnancies were hidden on-screen (McFadden performed a complex stunt in  just before discovering she was pregnant), while a surrogate pregnancy was written into Visitor's character, Kira Nerys, in . Dawson's pregnancy was seen onscreen in the episodes  and . It was written into the character as a holographic pregnancy.

External links
 
 

de:Schwangerschaft
Sex and reproduction