By Jose Cortes

SAN SEBASTIAN TUTLA, Mexico At a dusty migrant camp in southern Mexico, 19-year-old Luzmar Rodriguez is leaning on a reclined seat at the back of a gray van while a midwife presses a stethoscope against her stomach.

"It's the first time I've heard the baby's heartbeat," she said.

As record numbers of migrants looking to reach the United States trek the perilous Darien Gap jungles between Colombia and Panama, many have reported rapes. A growing number of those making the journey are children.

Rodriguez, a Venezuelan woman who lived in Chile for a year before setting out for the United States with her husband and three-year-old son, is planning to seek asylum at the border with Texas.

The makeshift midwives' station in the camp in Oaxaca state, where families sleep in small tents with little protection from sun and rain, is part of a network of midwives helping migrants that operates across Mexico.

Some 300 people sleep at the camp - which has no running water and fewer than 20 toilets - each day before taking buses toward Mexico City.

Leticia Serrano, a 50-year-old midwife from Texas, said many women are at greater risk of miscarrying due to difficulties traveling and poor access to water.

"Everything that hurts the body irritates the uterus," Serrano said. "Many find out they are pregnant when they leave the jungle."

Melanie Gonzalez, 22, has been traveling for two months since leaving Venezuela with her husband to seek work in the United States and send money back to her mother and two kids.

She underwent surgery in Venezuela to prevent future pregnancies, but later discovered she had a high-risk pregnancy.

At six-months pregnant, she, like many other women making the journey across Mexico faces numerous risks, including infections that can cause miscarriage and rough conditions. Gonzalez said she had received little help.

"Here what women need most is a place to sleep that isn't on rocks," Serrano said.

(Reporting by Jose Cortes; Writing by Sarah Morland; Editing by Rod Nickel)