As the condition is more prevalent in black women in the U.S. and the UK, it has been suggested to be an explanation for the higher rate of preterm birth in these populations. It is opined that bacterial vaginosis before or during pregnancy may affect the decidual inflammatory response that leads to preterm birth. The condition known as aerobic vaginitis can be a serious risk factor for preterm labor; several previous studies failed to acknowledge the difference between aerobic vaginitis and bacterial vaginosis, which may explain some of the contradiction in the results.Untreated yeast infections are associated with preterm birth.A review into prophylactic antibiotics (given to prevent infection) in the second and third trimester of pregnancy (13–42 weeks of pregnancy) found a reduction in the number of preterm births in women with bacterial vaginosis. These antibiotics also reduced the number of waters breaking before labor in full-term pregnancies, reduced the risk of infection of the lining of the womb after delivery (endometritis), and rates of gonococcal infection. However, the women without bacterial vaginosis did not have any reduction in preterm births or pre-labor preterm waters breaking. Much of the research included in this review lost participants during follow-up so did not report the long-term effects of the antibiotics on mothers or babies. More research in this area is needed to find the full effects of giving antibiotics throughout the second and third trimesters of pregnancy.A number of maternal bacterial infections are associated with preterm birth including pyelonephritis, asymptomatic bacteriuria, pneumonia, and appendicitis.
Pterygium (plural pterygia or pterygiums) refers to any wing-like triangular membrane occurring in the neck, eyes, knees, elbows, ankles or digits.The term comes from the Greek word pterygion meaning "wing". Types
Popliteal pterygium syndrome, a congenital condition affecting the face, limbs, or genitalia but named after the wing-like structural anomaly behind the knee
Pterygium (eye) or surfers eye, a growth on the cornea of the eye
Pterygium colli or webbed neck,  a congenital skin fold of the neck down to the shoulders
Pterygium inversum unguis or ventral pterygium, adherence of the distal portion of the nailbed to the ventral surface of the nail plate
Pterygium unguis or dorsal pterygium, scarring between the proximal nail fold and matrix

Pterygium of the eye
A pterygium reduces the vision in several ways:

Distortion of the corneal optics. This begins usually when the pterygium is greater than 2mm from the corneal edge (limbus). Disruption of the tear film. The tear film is the first lens in the eye. Pterygia are associated with eyelid inflammation, called Blepharitis. Growth over the corneal centre, which leads to dramatic reduction of vision. Induced anterior corneal scarring, which often remains after surgical removal.A pterygium of the eye grows very slowly. Usually it takes several years or decades to progress. Surgical removal
Indications for surgery, in order of decreasing importance:

Growth over the corneal centre. Reduced vision due to corneal distortion. Documented growth. Symptoms of discomfort. Cosmesis.Surgery is usually performed under local anaesthetic with light sedation as day surgery. The pterygium is stripped carefully off the surface of the eye.