Sister Wives season 6 may feature some major drama at the Brown household as Kody and Robyn are expecting a baby soon.

The official Facebook page for the popular show has recently posted a video featuring the newly married couple's journey so far.

This will be her fourth pregnancy and Kody will become the father of his 18th child. He already has 17 children from his wives (including the children from his fourth wife Robyn's previous marriage).

The page documents Robyn's pregnancy after her marriage to Kody in 2014 and updates fans about the baby's growth in the mother's womb.

At 16 weeks, #babybrown can now suck his or her thumb, and stretch those little limbs! How exciting for Robyn and Kody!

Posted by Sister Wives on Friday, July 24, 2015

However, the official TLC page for the reality TV show has refrained from mentioning any updates about the eldest wife of the Brown patriarch.

Since her divorce, Meri, the mother of one, has distanced herself from sharing any news about the Brown family. She even remained silent around her 25th wedding anniversary to the Brown patriarch.

After Robyn's baby news, Kody's second and third wives Janelle and Christine congratulated the couple, but Meri maintained a silence sparking rumours that she has moved out of the family.

Robyn, a mother of three, is in her 18th week of pregnancy and is due to give birth on 7 January. Fans suspect that the upcoming season of the popular show will mostly be about Kody and Robyn and their marital journey up to child birth.

Season 5 of TLC's popular family reality show ended on a shocking note when Meri Brown decided to divorce her polygamous husband so that he could marry Robyn and legally adopt her children from her previous marriage.

Meri was hailed by fans for her courageous sacrifice but fans were not too happy about the youngest sister wife. Some of them were unhappy about the recent news of her pregnancy.

"Robyn comes along and all of a sudden the other wives are forgotten," one fan wrote on the show's Facebook post. "I liked it when it was just the 3 wives..too much problems since Robyn came into picture. He tells Meri no to a baby and now having one with Robyn," wrote another.

Sister Wives season 6 will premiere in fall this year but TLC has not yet confirmed a date.