Woman asks for advice after finding out her 15-year-old sister is pregnant

What would you do in this situation?

A mum has taken to Mumsnet after she found out her sister is pregnant. She found a positive pregnancy test in her sister's clothes, but doesn't know whether to tell their mother. She wrote:

"We were going to go swimming as a family and I didn't have any clean nickers packed! I'm staying in a hotel so couldn't just grab some from my own stuff. "DSister said no problem, go and grab some from my shelf. I did, and inside was a pregnancy test. Positive. "Shocked, I grabbed the nickers and left. It was extremely difficult to cover up my shock. "What do I do? Do I tell our Mum? DSister is 15. "She and our youngest sister decided to go off on their own and I haven't seen her since. We will be seeing both sisters later at the house. I tried asking if I could have a word earlier and she said 'not now, please.'"

Many users replied saying that they think the best course of action is talking to her sister first, before even attempting to go to their mother. One said:

"Speak to your sister first. Offer to support he whatever her decision. Do not tell your mum. Your sister will never forgive you. "If you can't speak to sister then do nothing."

Another wrote:

"Don’t tell your mum. Talk to your sister. Be supportive and non judgemental. Listen to her. Don't overreact."

While one more commented:

"Talk to her. Tell her you found it. WhatsApp, Facebook, a letter - you can't pretend you 'cant' communicate with her. Of course you can. "She may not be pregnant. The test could be months old."

Have you ever been in this situation? How do you think this woman should handle it?