As a coach, you can help keep girls healthy and in the game.
Girls may experience different challenges around puberty, and it is all new to them.
They also may be more likely to endure shoulder injuries, ACL tears, concussions, and eating disorders. You are positioned to notice things as they are happening. Some of the specific health issues that your female athletes may experience include the following:
The female athlete triad:
This condition describes the interrelationship between bone health, menstrual function, and proper nutrition. Eating enough calories for healthy growth and development, as well as fueling their sports activities is essential. Coaches, consider inviting a nutritionist to meet with your athletes to talk about optimal nutrition specific to your sport and level of competition.
ACL tears occur five to eight times more frequently in female athletes due to anatomical and muscular differences and body mechanics. As a coach, consider incorporating functional strength training and neuromuscular training with plyometrics and agility drills.
Some studies suggest that girls are at a higher risk of concussion than boys. “Among youth basketball players, for example, 11.5% of girls seen in the ER are diagnosed with concussions, compared with 7.2% of boys. Among soccer players, it's 17.1% of girls compared with 12.4% of boys.” . While research is limited, theories explaining this increased susceptibility include girls having smaller mass of the head and neck and less developed neck muscles. The data that girls may also have more severe concussion symptoms that take longer to resolve could be due to girls reporting their injuries more readily. Coaches, pay attention to subtle symptoms, and ensure your athletes are wearing appropriate equipment.
What and how you as a coach communicate about pain or injury is also critical to your athletes’ well-being. Encourage your athletes to trust their bodies and communicate with you about pain and discomfort that they are experiencing. If you have taken the steps described earlier to develop trust and relationships with the girls on your team, it is likely they will feel more willing to let you know how they feel and what is going on with their bodies. Be careful not to explicitly or inadvertently promote a culture of “pushing through the pain.” Remember, you want girls to stay in sports, and an injury could sideline them indefinitely.
Menstrual cycle and sports
In an interview with The Telegraph, USWNT’s fitness coach Dawn Scott said, “One emerging issue in women’s sport is the menstrual cycle and its impact on performance, player health and injury risk.” 
In 2019, Dawn Scott led an initiative to end period taboo for the USA World Cup team. Her partner, Dr. George Bruinvels, stated to The Telegraph, “There’s no evidence that someone can’t perform to their best at any time in their cycle – if they are proactive about taking steps.”  Normal, healthy menstrual cycles should not get in the way of competing, and research shows that performance stays about the same during menstruation.
Menstrual cycles can however provide information about overall health, including whether or not girls are getting proper nutrition or training too hard. Issues with menstruation indicate hormonal disruptions, which can impact bone health and density. Healthy estrogen and other hormone levels help build bones and keep them from breaking down.
Research from the Boston Children's Hospital’s Female Athlete program states that “an amenorrheic athlete is two to four times more at risk for a stress fracture than an athlete who has regular periods.” 
Research also states that exercising during menstruation can soothe cramps and PMS symptoms. 
Social issues related to menstruation
Girls may have all kinds of issues around menstruation, and it is all new to them. You as a coach may be the adult in their lives best positioned to notice things as they are happening, and you could significantly help a girl by addressing them with her and her parents or guardians.
There are also ways that you as a coach can be sensitive and thoughtful about this stage of adolescent development. For example, you could talk generally about where supplies are kept for girls who may need them during practice. You can choose uniforms that are darker colored to avoid anxiety about leakage. You can address nutritional needs of female athletes who are at risk for iron depletion. Normalizing discussion of the menstrual cycle rather than avoiding the topic will increase their comfort around it.
“For the 15-year-old girl who doesn’t have the support of a national team, I want to make it so she can talk about it with a female coach and a male coach...We need to make people aware of it and not embarrassed by it.” - Dawn Scott