A married US couple's wish to start a family was a long, and often heartbreaking, process. But it looks like their prayers have finally been answered – Lindsay Vargas and her husband Brian have been blessed with not one but two babies together.

The Nebraska couple had struggled for the last 13 years to conceive a child, with 15 miscarriages, three failed adoptions, two surrogacy attempts and an ectopic pregnancy. The duo, who got married in 2005, spent around $500,000 (£376,900) for the procedures but all of that went in vain... until now.

The pair is now all set to welcome their twins via a surrogate, just a few months after adopting their first child. Lindsay's sister, Kelly O'Toole, is carrying the twins – a girl and a boy – and is due to give birth to them in April, the Daily Mail reported.

Talking about her struggles to Yahoo Lifestyle, the 35-year-old would-be-mother-of-twins said, "When we started trying, I figured it would take a few months to get pregnant." But after trying for one-and-a-half years, Lindsay said she visited her obstetrician-gynaecologist (OB-GYN), who prescribed Clomid – a medication that helps trigger ovulation and the release of eggs for fertilisation.

"My doctor kept increasing the dose beyond the recommended length of time and didn't monitor me. As a result, I developed a softball-sized cyst in my ovaries," the hair salon owner said.

She added that she had to undergo a surgery to remove the cyst, but it stopped her from getting pregnant naturally. The couple then began looking into artificial insemination procedures.

"I kept getting pregnant, but I'd miscarry each time after about eight weeks," Lindsay said of the five-year process. "We'd hear the baby's heartbeat at our first ultrasound, but at the next appointment, there would be no heartbeat," she continued.

When artificial insemination failed as well, Lindsay and Brian then started looking at the option of surrogacy. Her elder sister, Kelly, offered to carry their child but Lindsay was not ready for it due to the fact that it would burden her sister, who was already a mother-of-three. Eventually, though, she came around to the idea.

However, their plans were disrupted again when Kelly was diagnosed with a benign tumour and doctors had to remove it and also had to take out one of her ovaries.

The couple then set up a Go Fund Me page to find another surrogate. Their campaign gained a lot of attention, and the couple eventually got an offer from a woman asking whether they would consider adopting her unborn child.

Hesitant at first, Lindsay and Brian agreed to it and adopted the baby girl named Henley, who was born on 15 October.

But there was more good news in store. Soon after Henley's arrival, the couple were informed that Kelly had became pregnant with two embryos which had remained from their previous effort.

Lindsay now thinks that her family is complete and hopes her story will help other couples who are also facing similar problems. "I get so many messages from women struggling with infertility – why is the topic so shameful? I want to turn this into something positive for others. We've been through hell and back, but it's worth it," she added.