i know that Bryce Dallas Howard's pregnancy was written into the script when she was filming the Terminator: Salvation movie because they showed her fully pregnant in several scenes during the movie..

Just a fyi, Bryce Dallas Howard is the daughter of Ron Howard who played Opie on The Andy Griffith Tv Show many years ago..

Was she the baby Fonzie helped deliver?

In My Wife & Kids, Tisha Campbell missed out the first few episodes of Season 2 due to being pregnant, but she still made a couple of brief appearances in the first two episodes (including a scene where she sneezes out a baby).

Here's a couple GIFs: [1] [2]

   

Gillian Anderson's pregnancy was briefly out to use on The X-Files.

(May 10, 2022, 9:55 am)LTKNT101 It wasn’t a movie but Lucille Ball’s pregnancy was written into her character in a few episodes of I love Lucy. They even had her character give birth off screen on the same day she was actually at the hospital giving birth.

Her husband Desi Arnez filmed his scenes then rushed off to be with her. This was the 1950s when pregnancy was something you didn’t talk about publicly. Characters on tv could not say pregnant. They had to say expecting.

With that kind of censorship going on I’m surprised the producers allowed Lucy’s pregnancy to become part of the show. They could have easily given her maternity leave and wrote her character to be visiting her mother out of town or something to explain her absence to the audience.

You never saw Lucy’s bump on the show because she kept it hidden under very bulky 1950s maternity clothing which looked ridiculous.

Lucille Ball and Desi Arnez produced the show and they owned the studio (Desilu) that was later bought by Paramount.
Trivia fact: Lucille Ball was the first actress to appear pregnant while pregnant on American TV.

To continue with some of the TV ones, Rachel Luttrell had her pregnancy written into Stargate Atlantis Season 4

And Desi Jr. was on the 1st TV GUIDE cover

Not a movie, but it did happen for a show. In Season 2 of Terminator: The Sarah Connor Chronicles, Busy Phillipps’s pregnancy was written into the show and was somewhat a main part of the character she played, Kacy Cotton.

Always wondered this: 1-> why do women's pregnancies get written into/put into shows & movies? Why not have someone temporarily replace them until their "leave" is over?
2-> why do actresses film when their pregnant? Wouldn't finding a temporary actress be better until they are done on leave?