My wife is pregnant in 7w and have some cotton...

according to how do you describe the discharge , you are having the most common vaginal infection  , the so called bacterial vaginosis

what is the treatment of bacterial vaginosis?

1. Antibiotics since it is bacterial infection  as metronidazole and clindamycin wither it is orally taken or vaginally applied , other choices is penicillin
2. conservative measures as keep good hygien , treat any associated infection as UTI

what is the cause of Bacterial Vaginosis?

it is bacterial infection caused commonly by

1. Gardnerella vaginalis the most common type
2. lactobacillus
3. streptococcus viridans

what are the associated symptoms with baterial vaginosis?

1. Vaginal odor
2. vaginal discharge
3. itching
4. redness 
5. dysparunia which is pain during intercourse
6. dysurea which is burning sensation while urinate

how do we diagnose Bacterial Vaginosis?

1. clinical Exam by demonstrating the characters of smell color and appearance of Bacterial Vaginosis discharge
2. microspic inspection of type of cell called clue cell that indicate this type of infection
3. culture the discharge for gardinella vaginalis microorganism
4. chemical features of the discharge as the acidic nature of it