Mary Queen of Scots (2018)

PREGNANCY: Following a sex scene, Mary is next shown pregnant at ~1:00:00. Soon after (~1:03:00), she’s shown in the bath, and although she still wears a gown, it is mostly see-through. She also reacts to the baby kicking. Aside from that, she mainly wears dresses and gowns. She gives birth in a short montage with little shown at ~1:22:00.

Double Lover (2017)

PREGNANCY/OTHER: The main character is revealed to be pregnant at ~1:07:00, followed by a short ultrasound at ~1:11:00. She’s small for most of the runtime, until late into the film (1:34:00) where visible movement starts to happen and her stomach bloats up somewhat before it slowly splits open and a tiny hand comes through. The epilogue of the film reveals that she wasn’t pregnant, but instead had been carrying the undeveloped fetus of her twin, and the events of most of the film had been delusions/hallucinations.

Hells (2008)

PREGNANCY/EXPANSION: When learning about the life of Cain and Abel (~1:01:00), a couple pictures are shown of Eve during her pregnancies for the two. Later in the film (~1:36:00), the classmates get filled with the physical manifestation of negative thoughts that transform them into demons. One is shown with her belly expanding as the thoughts are forced down her throat.

(Credit to pumpkinlol101 for the suggestion.)

Neighbors 2: Sorority Rising (2016)

PREGNANCY: The opening scene has Kelly getting morning sickness while having sex with Mac. The rest of the film takes place a few months later, so she’s got a small belly. Their friends are also expecting, and she appears to be further along. At ~36 minutes in, they have their friends briefly pose as their neighbors while in costume as Jewish people. At ~45 minutes in, they sneak into a tailgating party with the women dressed as cheerleaders. Following that, there’s a brief sex scene between Kelly and Mac. At ~1:06:00, the friend starts getting contractions, but writes them off as cramps. When she’s shown again at ~1:16:00, the baby’s leg is hanging out of her. The ending of the film skips over the rest of Kelly’s pregnancy.

The Brothers Solomon (2007)

PREGNANCY: Two awkward brothers hire a surrogate so their dying dad can be a grandfather. It skims through the pregnancy itself, hitting the third trimester at ~56 minutes in, starting with a barely shown ultrasound. Couple scenes later (~58 minutes in), there’s a scene in a birthing class. After which, she changes her mind about giving up the baby and disappears. She reappears at ~1:18:00 and one of the brothers blows an air horn in celebration, which sends her into labor. She’s brought to a hospital and gives birth.

(Credit to superpfb for the suggestion.)